Chapter 8. SqlTool

## Chapter 8. SqlTool

### SqlTool Manual

### Blaine Simpson

HSQLDB Development Group
`<blaine.simpson@admc.com>`

### Dan Shinton

HSQLDB Development Group
`<dan@shinton.net>`

$Date: 2006/03/16 22:47:19 $

## Purpose

This document explains how to use SqlTool, the main purpose of which is to read your SQL text file or stdin, and execute the SQL commands therein against a JDBC database. There are also a great number of features to facilitate both interactive use (such as command-line editing and PL aliases) and automation (such as scripting variables and SQL transaction control and error handling).

Some of the examples below use quoting which works exactly as-is for any Bourne-compatible UNIX shell. (Only line-continuation would need to be changed for C-compatible UNIX shells). I have not yet tested these commands on Windows, and I doubt whether the quoting will work just like this (though it is possible). SqlTool is still a very useful tool even if you have no quoting capability at all.

If you are using SqlTool from a HSQDLB distribution before version 1.8.0.0 final, you should use the documentation with that distribution (because, for brevity, I do not here indicate changes made to behavior before 1.8.0.0 final). This document is now updated for the current versions of SqlTool and SqlFile at the time I am writing this (versions 1.50 and 1.130 correspondingly, SqlFile is the class which does most of the work for SqlTool). Therefore, if you are using a version of SqlTool or SqlFile that is more than a couple revisions greater, you should find a newer version of this document. (The imprecision is due to content-independent revision increments at build time, and the likelihood of one or two behavior-independent bug fixes after public releases). The startup banner will report both versions when you run SqlTool interactively.

### Recent changes

This section lists changes to SqlTool since the last major release of HSQLDB. For this revision of this document, this list consists of significant changes made to SqlTool AFTER the final 1.8.0.0 HSQLDB release.

- Fixed bug where PL "end" command was still requiring old syntax (wrt white space). Fixed for HSQLDB v. 1.8.0.2.
- Fixed NPE sometimes encountered when fetching null Timestamp values. Fixed for HSQLDB v. 1.8.0.2.
- Implemented new \dr command for HSQLDB and Sybase servers. Implemented \du for Sybase. Added for HSQLDB v. 1.8.0.3.
- Implemented CSV eXport and iMport commands \x and \m. Added for HSQLDB v. 1.8.0.3.
- Implemented method for specifying RC file parameters as a command-line switch. Modified SqlTool to now accepts case insensitive command-line switches. Added for HSQLDB v. 1.8.1.

When recently changed or added features (i.e, those items in the preceding list) are described in the main document below, there is a Note at that point indicating when the feature was added or changed.

## The Bare Minimum You Need to Know to Run SqlTool

### Warning

If you are using an Oracle database server, it will commit your current transaction if you cleanly disconnect, regardless of whether you have set auto-commit or not. This will occur if you exit SqlTool (or any other client) in the normal way (as opposed to killing the process or using Ctrl-C, etc.). This is mentioned in this section only for brevity, so I don't need to mention it in the main text in the many places where auto-commit is discussed. This behavior has nothing to do with SqlTool. It is a quirk of Oracle.

If you want to use SqlTool, then you either have an SQL text file, or you want to interactively type in SQL commands. If neither case applies to you, then you are looking at the wrong program.

Procedure 8.1. To run SqlTool...

1. Copy the file `sqltool.rc` from the directory `src/org/hsqldb/sample` of your HSQLDB distribution to your home directory and secure access to it if your home directory is accessible to anybody else. This file will work as-is for a Memory Only database instance; or if your target is a HSQLDB Server running on your local computer with default settings and the password for the "sa" account is blank (the sa password is blank when new HSQLDB database instances are created). Edit the file if you need to change the target Server URL, username, password, character set, JDBC driver, or TLS trust store as documented in the RC File Authentication Setup section.

   OR

   Use the `--inlineRc` command-line switch to specify your connection parameters as documented in the Using Inline RC Authentication section.

2. Find out where your hsqldb.jar file resides. It typically resides at HSQLDB_HOME`/lib/hsqldb.jar` where HSQLDB_HOME is the base directory of your HSQLDB software installation. For this reason, I'm going to use "$HSQLDB_HOME/lib/hsqldb.jar" as the path to `hsqldb.jar` for my examples, but understand that you need to use the actual path to your own `hsqldb.jar` file.

3. Run

           java -jar $HSQLDB_HOME/lib/hsqldb.jar --help

   to see what command-line arguments are available. Note that you don't need to worry about setting the CLASSPATH when you use the `-jar` switch to `java`. Assuming that you set up your SqlTool RC file at the default location and you want to use the HSQLDB JDBC driver, you will want to run something like

           java -jar $HSQLDB_HOME/lib/hsqldb.jar mem

   for interactive use, or

           java -jar $HSQLDB_HOME/lib/hsqldb.jar --sql 'SQL statement' mem

   or

           java -jar $HSQLDB_HOME/lib/hsqldb.jar mem filepath1.sql...

   where `mem` is an urlid, and the following arguments are paths to text SQL files. For the filepaths, you can use whatever wildcards your operating system shell supports.

   The urlid `mem` in these commands is a key into your RC file, as explained in the RC File Authentication Setup section. Since this is a Memory Only database, you can use SqlTool with this urlid immediately with no database setup whatsoever (however, you can't persist any changes that you make to this database). The sample sqltool.rc file also defines the urlid "localhost-sa" for a local HSQLDB Server. At the end of this section, I explain how you can load some sample data to play with, if you want to.

### Important

SqlTool does not commit DML changes by default. This leaves it to the user's disgression whether to commit or rollback their modifications. Remember to either run the command `commit;` before quitting SqlTool, or use the `--autoCommit` command-line switch.

If you put a file named `auto.sql` into your home directory, this file will be executed automatically every time that you run SqlTool interactively and without the `--noAutoFile` switch.

To use a JDBC Driver other than the HSQLDB driver, you can't use the `-jar` switch because you need to modify the classpath. You must add the hsqldb.jar file and your JDBC driver classes to your classpath, and you must tell SqlTool what the JDBC driver class name is. The latter can be accomplished by either using the "--driver" switch, or setting "driver" in your config file. The RC File Authentication Setup section. explains the second method. Here's an example of the first method (after you have set the classpath appropriately).

    java org.hsqldb.util.SqlTool --driver oracle.jdbc.OracleDriver urlid

### Tip

If the tables of query output on your screen are all messy because of lines wrapping, the best and easiest solution is usually to resize your terminal emulator window to make it wider. (With some terms you click & drag the frame edges to resize, with others you use a menu system where you can enter the number of columns).

### Non-displayable Types

There are many SQL types which SqlTool (being a text-based program) can't display properly. This includes the SQL types `BLOB`, `JAVA_OBJECT`, `STRUCT`, and `OTHER`. When you run a query that returns any of these, SqlTool will save the very first such value obtained to the binary buffer and will not display any output from this query. You can then save the binary value to a file, as explained in the Storing and retrieving binary files section.

There are other types, such as `BINARY`, which JDBC can make displayable (by using ResultSet.getString()), but which you may very well want to retrieve in raw binary format. You can use the \b command to retrieve any-column-type-at-all in raw binary format (so you can later store the value to a binary file).

Another restriction which all text-based database clients have is the practical inability for the user to type in binary data such as photos, audio streams, and serialized Java objects. You can use SqlTool to load any binary object into a database by telling SqlTool to get the insert/update datum from a file. This is also explained in the Storing and retrieving binary files section.

### Desktop shortcuts

Desktop shortcuts and quick launch icons are useful, especially if you often run SqlTool with the same set of arguments. It's really easy to set up several of them-- one for each way that you invoke SqlTool (i.e., each one would start SqlTool with all the arguments for one of your typical startup needs). One typical setup is to have one shortcut for each database account which you normally use (use a different `--urlid` switch in each shortcut's Target specification.

Desktop icon setup varies depending on your Desktop manager, of course. I'll explain how to set up a SqlTool startup icon in Windows XP. Linux and Mac users should be able to take it from there, since it's easier with the common Linux and Mac desktops.

Procedure 8.2. Creating a Desktop Shortcut for SqlTool

1. Right click in the main Windows background.

2. New

3. Shortcut

4. Browse

5. Navigate to where your good JRE lives. For recent Sun JRE's, it installs to `C:\Program Files\Java\*\bin` by default (the * will be a JDK or JRE name and version number).

6. Select `java.exe`.

7. OK

8. Next

9. Enter any name

10. Finish

11. Right click the new icon.

12. Properties

13. Edit the Target field.

14. Leave the path to java.exe exactly as it is, including the quotes, but append to what is there. Beginning with a space, enter the command-line that you want run.

15. Change Icon... to a pretty icon.

16. If you want a quick-launch icon instead of (or in addition to) a desktop shortcut icon, click and drag it to your quick launch bar. (You may or may not need to edit the Windows Toolbar properties to let you add new items).

### Loading sample data

If you want some sample database objects and data to play with, execute the `sampledata.sql` SQL file. `sampledata.sql` resides in the `src/org/hsqldb/sample` directory of your HSQLDB distribution. Run it like this from an SqlTool session

    \i HSQLDB_HOME/src/org/hsqldb/sample/sampledata.sql

where HSQLDB_HOME is the base directory of your HSQLDB software installation.

For memory-only databases, you'll need to run this every time that you run SqlTool. For other (persistent) databases, the data will reside in your database until you drop the tables.

## RC File Authentication Setup

RC file authentication setup is accomplished by creating a text RC configuration file. In this section, when I say configuration or config file, I mean an RC configuration file. RC files can be used by any JDBC client program that uses the org.hsqldb.util.RCData class-- this includes SqlTool, DatabaseManager, DatabaseManagerSwing. You can use it for your own JDBC client programs too.

The following sample RC file resides at `src/org/hsqldb/sample/sqltool.rc` in your HSQLDB distribution.

Example 8.1. Sample RC File

    # $Id: sqltool.rc,v 1.17 2005/11/06 18:01:49 unsaved Exp $

    # This is a sample RC configuration file used by SqlTool, DatabaseManager,
    # and any other program that uses the org.hsqldb.util.RCData class.

    # You can run SqlTool right now by copying this file to your home directory
    # and running
    #    java -jar /path/to/hsqldb.jar mem
    # This will access the first urlid definition below in order to use a
    # personal Memory-Only database.

    # If you have the least concerns about security, then secure access to
    # your RC file.
    # See the documentation for SqlTool for various ways to use this file.

    # A personal Memory-Only database.
    urlid mem
    url jdbc:hsqldb:mem:memdbid
    username sa
    password

    # This is for a hsqldb Server running with default settings on your local
    # computer (and for which you have not changed the password for "sa").
    urlid localhost-sa
    url jdbc:hsqldb:hsql://localhost
    username sa
    password

    # Template for a urlid for an Oracle database.
    # You will need to put the oracle.jdbc.OracleDriver class into your
    # classpath.
    # In the great majority of cases, you want to use the file classes12.zip
    # (which you can get from the directory $ORACLE_HOME/jdbc/lib of any
    # Oracle installation compatible with your server).
    # Since you need to add to the classpath, you can't invoke SqlTool with
    # the jar switch, like "java -jar .../hsqldb.jar..." or
    # "java -jar .../hsqlsqltool.jar...".
    # Put both the HSQLDB jar and classes12.zip in your classpath (and export!)
    # and run something like "java org.hsqldb.util.SqlTool...".

    #urlid cardiff2
    #url jdbc:oracle:thin:@aegir.admc.com:1522:TRAFFIC_SID
    #username blaine
    #password secretpassword
    #driver oracle.jdbc.OracleDriver

    # Template for a TLS-encrypted HSQLDB Server.
    # Remember that the hostname in hsqls (and https) JDBC URLs must match the
    # CN of the server certificate (the port and instance alias that follows
    # are not part of the certificate at all).
    # You only need to set "truststore" if the server cert is not approved by
    # your system default truststore (which a commercial certificate probably
    # would be).

    #urlid tls
    #url jdbc:hsqldb:hsqls://db.admc.com:9001/lm2
    #username blaine
    #password asecret
    #truststore /home/blaine/ca/db/db-trust.store

    # Template for a Postgresql database
    #urlid blainedb
    #url jdbc:postgresql://idun.africawork.org/blainedb
    #username blaine
    #password losung1
    #driver org.postgresql.Driver

    # Template for a MySQL database.  MySQL has poor JDBC support.
    #urlid mysql-testdb
    #url jdbc:mysql://hostname:3306/dbname
    #username root
    #username blaine
    #password hiddenpwd
    #driver com.mysql.jdbc.Driver

    # Note that "databases" in SQL Server and Sybase are traditionally used for
    # the same purpose as "schemas" with more SQL-compliant databases.

    # Template for a Microsoft SQL Server database
    url jdbc:microsoft:sqlserver://hostname;DatabaseName=DbName;SelectMethod=Cursor
    # The SelectMethod setting is required to do more than one thing on a JDBC
    # session (I guess Microsoft thought nobody would really use Java for
    # anything other than a "hello world" program).
    # This is for Microsoft's SQL Server 2000 driver (requires mssqlserver.jar
    # and msutil.jar).
    driver com.microsoft.jdbc.sqlserver.SQLServerDriver
    username myuser
    password hiddenpwd

    # Template for a Sybase database
    urlid sybase
    url jdbc:sybase:Tds:hostname:4100/dbname
    username blaine
    password hiddenpwd
    # This is for the jConnect driver (requires jconn3.jar).
    driver com.sybase.jdbc3.jdbc.SybDriver

You can put this file anywhere you want to, and specify the location to SqlTool/DatabaseManager/DatabaseManagerSwing by using the `--rcfile` argument. If there is no reason to not use the default location (and there are situations where you would not want to), then use the default location and you won't have to give `--rcfile` arguments to SqlTool/DatabaseManager/DatabaseManagerSwing. The default location is `sqltool.rc` or `dbmanager.rc` in your home directory (corresponding to the program using it). If you have any doubt about where your home directory is, just run SqlTool with a phony urlid and it will tell you where it expects the configuration file to be.

        java -jar $HSQLDB_HOME/lib/hsqldb.jar x

The config file consists of stanza(s) like this:

        urlid web
        url jdbc:hsqldb:hsql://localhost
        username web
        password webspassword

These four settings are required for every urlid. (There are optional settings also, which are described a couple paragraphs down). You can have as many blank lines and comments like

        # This comment

in the file as you like. The whole point is that the urlid that you give in your SqlTool/DatabaseManager command must match a urlid in your configuration file.

### Important

Use whatever facilities are at your disposal to protect your configuration file.

It should be readable, both locally and remotely, only to users who run programs that need it. On UNIX, this is easily accomplished by using `chmod/chown` commands and making sure that it is protected from anonymous remote access (like via NFS, FTP or Samba).

You can also put the following optional settings into a urlid stanza. The setting will, of course, only apply to that urlid.

charset
  This is used by the SqlTool program, but not by the DatabaseManager programs. See the Character Encoding section of the Non-Interactive section. You can, alternatively, set this for one SqlTool invocation by setting the system property sqlfile.charset . Defaults to `US-ASCII`.
driver
  Sets the JDBC driver class name. You can, alternatively, set this for one SqlTool/DatabaseManager invocation by using the command line switch --driver. Defaults to org.hsqldb.jdbcDriver.
truststore
  TLS trust keystore store file path as documented in the TLS chapter. You usually only need to set this if the server is using a non-publicly-certified certificate (like a self-signed self-ca'd cert).

Property and SqlTool command-line switches override settings made in the configuration file.

## Using Inline RC Authentication

Inline RC authentication setup is accomplished by using the `--inlineRc` command-line switch on SqlTool. The `--inlineRc` command-line switch takes two required (URL and USER) and three optional arguments seperated by commas.

`URL`
  The JDBC URL of the database you wish to connect to.
`USER`
  The username to connect to the database as.
`DRIVER`
  The JDBC driver class name. Defaults to org.hsqldb.jdbcDriver.
`CHARSET`
  Sets the character encoding. Defaults to `US-ASCII`.
`TRUST`
  The TLS trust keystore file path as documented in the TLS chapter.

Here is an example of invoking SqlTool to connect to a standalone database.

        java -jar $HSQLDB_HOME/lib/hsqldb.jar
             --inlineRc URL=jdbc:hsqldb:file:/home/dan/dandb,USER=dan

For security reasons, you cannot specify the password as an argument. You will be prompted for a password as part of the login process.

## Using the current version of SqlTool with an older HSQLDB distribution.

This procedure will allow users of a legacy version of HSQLDB to use all of the new features of SqlTool. You will also get the new versions of the DatabaseManagers! This procedure works for distros going back to 1.7.3.3 at least, probably much farther.

These instructions assume that you are capable of running an Ant build. See the Building HSQLDB chapter.

1. Download and extract a current HSQLDB distribution. If you don't want to use the source code, documentation, etc., you can use a temporary directory and remove it afterwards.

2. Cd to the build directory under the root directory where you extracted the distribution to.

3. Run `ant hsqldbutil`. Do not run `ant hsqltool`, because hsqlbutil.jar files contain the HSQLDB JDBC driver, and you can not use a newer JDBC driver with an older HSQLDB database.

4. If you're going to wipe out the build directory, copy `hsqldbutil.jar` to a safe location first.

5. For now on, whenver you are going to run SqlTool, make sure that you have this `hsqldbutil.jar` as the first item in your CLASSPATH. You can't run SqlTool with the "-jar" switch (because the -jar switch doesn't permit setting your own class path).

Here's a UNIX example where somebody wants to use the new SqlTool with their older HSQLDB database, as well as with Postgresql and a local application.

    CLASSPATH=/path/to/hsqldbutil.jar:/home/bob/classes:/usr/local/lib/pg.jdbc3.jar
    export CLASSPATH
    java org.hsqldb.util.SqlTool urlid

## Interactive

Do read the The Bare Minimum section before you read this section.

You run SqlTool interactively by specifying no SQL filepaths on the SqlTool command line. Like this.

        java -jar $HSQLDB_HOME/lib/hsqldb.jar urlid

Procedure 8.4. What happens when SqlTool is run interactively (using all default settings)

1. SqlTool starts up and connects to the specified database, using your SqlTool configuration file (as explained in the RC File Authentication Setup section).

2. SQL file `auto.sql` in your home directory is executed (if there is one),

3. SqlTool displays a banner showing the SqlTool and SqlFile version numbers and describes the different command types that you can give, as well as commands to list all of the specific commands available to you.

You exit your session by using the "\q" special command or ending input (like with Ctrl-D or Ctrl-Z).

### Important

Every command (regardless of type) and comment must begin at the beginning of a line (or immediately after a comment ends with "*/").

You can't nest commands or comments. You can only start new commands (and comments) after the preceding statement has been terminated. (Remember that if you're running SqlTool interactively, you can terminate an SQL statement without executing it by entering a blank line).

(Special Commands, Buffer Commands and PL Commands always consist of just one line. Any of these commands or comments may be preceded by space characters.)

These rules do not apply at all to Raw Mode. Raw mode is for use by advanced users when they want to completely bypass SqlTool processing in order to enter a chunk of text for direct transmission to the database engine.

When you are typing into SqlTool, you are always typing part of the current command. The buffer is the last SQL command. If you're typing an SQL command, then the previous SQL command will be in the buffer, not the one you are currently typing. The current command could be any type of command, but only SQL When you type command-editing commands, the current command is the editing command (like "`:s/tbl/table/`"), the result of which is to modify the SQL command in the buffer (which can thereafter be executed). The ":a" command (with no argument) is special in that it takes a copy of the SQL command in the buffer and makes that the current command, leaving you in a state where you are appending to that now current command. The buffer is the zeroeth item of the SQL command history.

### Command Types

Command types

### Note

Above, we said that if you enter an SQL command, one SQL command corresponds to one SqlTool command. This is the most typical usage, however, you can actually put multiple SQL statements into one SQL command. One example would be

        INSERT INTO t1 VALUES(0); SELECT * FROM t1;

This is one SqlTool command containing two SQL statements. See the Chunking section to see why you may want to chunk SQL commands, how, and the implications.

SQL Statement

  Any command that you enter which does not begin with "\", ":", or "* " is an SQL Statement. The command is not terminated when you hit ENTER, like most OS shells. You terminate SQL Statements with either ";" at the end of a line, or with a blank line. In the former case, the SQL Statement will be executed against the SQL database and the command will go into the command buffer and SQL command history for editing or viewing later on. In the former case, execute against the SQL database means to transmit the SQL text to the database engine for execution. In the latter case (you end an SQL Statement with a blank line), the command will go to the buffer and SQL history, but will not be executed (but you can execute it later from the buffer). (See the note immediately above about multiple SQL statements in one SqlTool command).

  (Blank lines are only interpreted this way when SqlTool is run interactively. In SQL files, blank lines inside of SQL statements remain part of the SQL statement).

  As a result of these termination rules, whenever you are entering text that is not a Special Command, Buffer Command, or PL Command, you are always appending lines to an SQL Statement. (In the case of the first line, you will be appending to an empty SQL statement. I.e. you will be starting a new SQL Statement).

Special Command
  Run the command "\?" to list the Special Commands. All of the Special Commands begin with "\". I'll describe some of the most useful Special Commands below.
Buffer Command
  Run the command ":?" to list the Buffer Commands. All of the Buffer Commands begin with ":". Buffer commands operate upon the command "buffer", so that you can edit and/or (re-)execute previously entered commands.
PL Command

  Procedural Langage commands. Run the command "*?" to list the PL Commands. All of the PL Commands begin with "*". PL commands are for setting and using scripting variables and conditional and flow control statements like `* if` and `* while`. A few PL features (such as PL aliases and updating and selecing data directly from/to files) can be a real convenience for nearly all users, so these features will be discussed briefly in this section. More detailed explanation of PL variables and the other PL features, with examples, are covered in the SqlTool Procedural Language section.

Raw Mode
  The descriptions of command-types above do not apply to Raw Mode. In raw mode, SqlTool doesn't interpret what you type at all. It all just goes into a buffer which you can send to the database engine. Beginners can safely ignore raw mode. You will never encounter it unless you run the "\." special command, or enter a PL/SQL command. See the Raw Mode section for the details.

### Special Commands

Essential Special Commands

\?
  help
\q
  quit
\dt [filter_substring]
\dv [filter_substring]
\ds [filter_substring]
\di [table_name]
\dS [filter_substring]
\da [filter_substring]
\dn [filter_substring]
\du [filter_substring]
\d* [filter_substring]

  Lists available objects of the given type.

  - t: non-system Tableѕ
  - v: Views
  - s: Synonyms
  - i: Indexes
  - S: System tableѕ
  - a: Aliases
  - n: schema Names
  - u: database Users
  - *: all table-like objects
  If your database supports schemas, then the schema name will also be listed.

  If you supply an optional filter substring, then only items which contain the given substring (in the object name or schema name) will be listed.

  ### Important

  The substring test is case-sensitive! Even though in SQL queries and for the "\d objectname" command object names are usually case-insensitive, for the \dX commands, you must capitalize the filter substring exactly as it will appear in the special command output. This is an inconvenience, since the database engine will change names in SQL to default case unless you double-quote the name, but that is server-side functionality which cannot (portably) be reproduced by SqlTool. You can use spaces and other special characters in the string.

  ### Tip

  Filter substrings ending with "." are special. If a substring ends with ".", then this means to narrow the search by the exact, case-sensitive schema name given. For example, if I run "\d* BLAINE.", this will list all table-like database objects in the "BLAINE" schema. The capitalization of the schema must be exactly the same as how the schema name is listed by the "\dn" command. You can use spaces and other special characters in the string. (I.e., enter the name exactly how you would enter it inside of double-quotes in an SQL command). This is an inconvenience, since the database engine will change names in SQL to default case unless you double-quote the name, but that is server-side functionality which cannot (portably) be reproduced by SqlTool.

  ### Important

  Indexes may not be searched for by substring, only by exact target table name. So if `I1` is an index on table `T1`, then you list this index by running "\di T1". In addition, many database vendors will report on indexes only if a target table is identified. Therefore, "\di" with no argument will fail if your database vendor does not support it.

\d objectname [filter]

  Lists names of columns in the specified table or view. `objectname` may be a base table name or a schema.object name.

  If you supply a filter string, then only columns with a name containing the given filter will be listed. The objectname is nearly always case-insensitive (depends on your database), but the filter is always case-sensitive. You'll find this filter is a great convenience compared to other database utilities, where you have to list all columns of large tables when you are only interested in one of them.

  ### Tip

  When working with real data (as opposed to learning or playing), I often find it useful to run two SqlTool sessions in two side-by-side terminal emulator windows. I do all of my real work in one window, and use the other mostly for \d commands. This way I can refer to the data dictionary while writing SQL commands, without having to scroll.

\s
  Shows the SQL command history. The SQL command history will show a number (a negative number) for each SQL Statement that has made it into the buffer so fare (by either executing or entering a blank line). You can then use the "\-" command (which is described next) to retrieve commands from the SQL history to work with. To list just the very last command, you would use the ":l" buffer command to list the buffer contents, instead of this command.
\-[3]

  Enter "\" followed by the command number from SQL history, like "\-3". That command will be written to the buffer so that you can execute it or edit it using buffer commands.

  (You can append a semicolon to a recall command in order to execute the recalled buffer immediately, like "\-3;". This is actually just a shortcut for running the Special Command "\-3" and the Buffer Command ":;".)

This list here includes only the essential Special Commands, but n.b. that there are other useful Special Commands which you can list by running `\?`. (You can, for example, execute SQL from external SQL files, and save your interactive SQL commands to files). Some specifics of these other commands are specified immediately below, and the Generating Text or HTML Reports section explains how to use the "\o" and "\H" special commands to generate reports.

Be aware that the `\!` Special Command does not work for external programs that read from standard input. You can invoke non-interactive and graphical interactive programs, but not command-line interactive programs.

SqlTool executes `\!` programs directly, it does not run an operating system shell (this is to avoid OS-specific code in SqlTool). Because of this, you can give as many command-line arguments as you wish, but you can't use shell wildcards or redirection.

The \w command can be used to store any command in your SQL history to a file. Just restore the command to the buffer (which is the 0th element of the history) with a command like "\-4" before you give the \w command.

### Buffer Commands

Buffer Commands

:?
  help
:;
  Executes the SQL statement in the current buffer against the database. This is an extremely useful command. It's easy to remember because it consists of ":", meaning Buffer Command; plus a line-terminating ";", which sends the preceding SQL to the database engine for execution.
:l
  (This is a lower case L). List the current contents of the buffer.
:a

  Enter append mode with the contents of the buffer as the current SQL Statement. Things will be exactly as if you physically re-typed the command that is in the buffer. Whatever line you type next will be appended to the SQL Statement. You can execute the command by terminating a line with ";", or send it back to the buffer by entering a blank line.

  You can, optionally, put a string after the :a, in which case this text will be appended and you will remain in append mode. (Unless the text ends with ';', in which case the resultant statement will be executed immediately). Note that if you do put text after the "a", exactly what you type immediately after "a" will be appended. If your buffer contains `SELECT x FROM mytab` and you run `a:le`, the resultant command will be `SELECT x FROM mytable`. If your buffer contains `SELECT x FROM mytab` and you run `a: ORDER BY y`, the resultant command will be `SELECT x FROM mytab ORDER BY y`. Notice that in the latter case the append text begins with a space character.

:s/from string/to string/switches

  This is the primary command for SqlTool command editing-- it operates upon the current buffer. The "to string" and the "switches" are both optional. To start with, I'll discuss the use and behavior if you don't supply any substitution mode switches.

  Don't use "/" if it occurs in either "from string" or "to string". You can use any character that you want in place of "/", but it must not occur in the from or to strings. Example

          :s@from string@to string@

  The to string is substituted for the first occurrence of the (case-specific)from string. The replacement will consider the entire SQL statement, even if it is a multi-line statement.

  All occurrences of "$" in the from string and the to string are treated as line breaks. For example, from string of "`*$FROM mytable`" would actually look for occurrences of

           *
           FROM mytable

  Here is a another meaningful example using $.

          :s/e)$/e) WHERE col1 is not null$/

  This command appends "`WHERE col1 is not null`" to the line(s) which end with "e)".

  The to string may be empty, in which case, occurrences of the from string are just deleted. For example

          :s/this//

  would remove the first occurrence of "this". (With the "g" substitution mode switch, as explained below, it would remove all occurrences of "this").

  Don't end a to string with ";" in attempt to make a SQL statement execute. There is a substitution mode switch to use for that purpose.

  You can use any combination of the substitution mode switches.

  - Use "i" to make the searches for from string case insensitive.

  - Use "g" to substitute globally, i.e., for all occurrences of from string which are found in the text under consideration.

  - Use ";" to execute the command immediately after the substitution is performed.

  - Use an integer (from 1 to 9) to narrow the text under consideration to a specific line of a multi-line buffer.

  The substitution facility doesn't support any regular expressions at all. When we stop supporting Java versions older than 1.4, I'll start supporting regular expressions and other advanced string manipulation functions.

### PL Commands

Essential PL Command

* VARNAME = value

  Set the value of a variable. If the variable doesn't exist yet, it will be created. The most common use for this is so that you can later use it in SQL statements, print statements, and PL conditionals, by using the `*{VARNAME}` construct.

  If you set a variable to an SQL statement (without the terminating ";") you can then use it as a PL alias like `*VARNAME`, as shown in this example.

  Example 8.2. Defining and using a PL alias (PL variable)

          * q = SELECT COUNT(*) FROM mytable
          \p The stored query is '*{q}'
          /q;
          /q WHERE mass > 200;

  If you put variable definitions into the SQL file `auto.sql` in your home directory, those aliases/variables will always be available for interactive use.

* load VARNAME /file/path.txt
  Sets VARNAME to the content of the specified ASCII file.
* prepare VARNAME
  Indicate that next command should be a SQL INSERT or UPDATE command containing one question mark. The value of VARNAME will be substuted for the ? variable. This does work for CLOB columns.
* VARNAME _
  When next SQL command is run, instead of displaying the rows, just store the very first column value to variable VARNAME. This works for CLOB columns. It also works with Oracle XML type columns if you use column labels and the `getclobval` function.
* dump VARNAME /file/path.txt
  Store the value of VARNAME to the specified ASCII file.

Note that PL commands are used to upload and download column values to/from local ASCII files, but the corresponding actions for binary files use the special \b commands. This is because PL variables are used for ASCII values and you can store any number of column values in PL variables. This is not true for binary column values. The \b commands work with a single binary byte buffer.

See the SqlTool Procedural Language section below for information on using variables in other ways, and information on the other PL commands and features.

### Storing and retrieving binary files

You can upload binary files such as photographs, audio files, or serialized Java objects into database columns. SqlTool keeps one binary buffer which you can load from files with the \bl command, or from a database query by doing a one-row query for any non-displayable type (including `BLOB`, `OBJECT`, and `OTHER`). In the latter case, the data returned for the first non-displayable column of the first result row will be stored into the binary buffer.

Once you have data in the binary buffer, you can upload it to a database column (including `BLOB`, `OBJECT`, and `OTHER` type columns), or save it to a file. The former is accomplished by the special command \bp followed by a prepared SQL query containing one question mark place-holder to indicate where the data gets inserted. The latter is accomplished with the \bd command.

You can also store the output from normal, displayable column into the binary buffer by using the special command \b. The very first column value from the first result row of the next SQL command will be stored to the binary byte buffer.

Example 8.3. Inserting binary data into database from a file

        \bl /tmp/favoritesong.mp3
        \bp
        INSERT INTO musictbl (id, stream) VALUES(3112, ?);

Example 8.4. Downloading binary data from database to a file

        SELECT stream FROM musictbl WHERE id = 3112;
        \bd /tmp/favoritesong.mp3

You can also store and retrieve text column values to/from ASCII files, as documented in the Essential PL Command section.

### SQL History

The SQL history shown by the \s command, and used by other commands, is truncated to 20 entries, since the utility comes from being able to quickly view the history list. You can change the history length by setting the system property `sqltool.historyLength` to an integer like

    java -Dsqltool.historyLength=40 -jar $HSQLDB_HOME/lib/hsqldb.jar urlid

The SQL history list explicitly does not contain Special, Buffer, or PL commands. It only contains SQL commands, valid or invalid, successful or unsuccessful. The reason for including bad SQL commands is so that you can recall and edit them if you want to. The same applies to the editing buffer (which is element 0 of the history).

### Shell scripting and command-line piping

You normally use non-interactive mode for piping. You specify "-" as the SQL file name. See the Piping and shell scripting subsection of the Non-Interactive chapter.

### Emulating Non-Interactive mode

You can run SqlTool interactively, but have SqlTool behave exactly as if it were processing an SQL file (i.e., no command-line prompts, error-handling that defaults to fail-upon-error, etc.). Just specify "-" as the SQL file name in the command line. This is a good way to test what SqlTool will do when it encounters any specific command in an SQL file. See the Piping and shell scripting subsection of the Non-Interactive chapter for an example.

## Non-Interactive

Read the Interactive section if you have not already, because much of what is in this section builds upon that. Even if your plans are to run SqlTool non-interactively, you should really learn to run it interactively because it's such a powerful debugging tool, and you can use it to prototype sql scripts.

### Important

If you're doing data updates, remember to issue a commit command or use the `--autoCommit` switch.

As you'll see, SqlTool has many features that are very convenient for scripting. But what really makes it superior for automation tasks (as compared to SQL tools from other vendors) is the ability to reliably detect errors and to control JDBC transactions.

### Giving SQL on the Command Line

If you just have a couple SQL commands to run, you can run them directly from the comand-line or from a shell script without an SQL file, like this.

        java -jar $HSQLDB_HOME/lib/hsqldb.jar --sql 'SQL statement' urlid

### Note

The `--sql` automatically implies `--noinput`, so if you want to execute the specified SQL before and in addition to an interactive session (or stdin piping), then you must also give the --stdinput switch.

### Note

SqlTool will automatically add a trailing semicolon to your `--sql` SQL. You may still give the trailing semicolon if you wish to, and you must still delimit multiple SQL commands with a simicolon, of course.

Since SqlTool transmits SQL statements to the database engine only when a line is terminated with ";", if you want feedback from multiple SQL statements in an --sql expression, you will need to use functionality of your OS shell to include linebreaks after the semicolons in the expression. With any Bourne-compatible shell, you can include linebreaks in the SQL statements like this.

        java -jar $HSQLDB_HOME/lib/hsqldb.jar --sql 'SQL statement' urlid '
            SQL statement number one;
            SQL statement
                number two;
            SQL statement three;
        ' urlid

If you don't need feedback, just separate the SQL commands with semicolons and the entire expression will be chunked.

The --sql switch is very useful for setting shell variables to the output of SQL Statements, like this.

        # A shell script
        USERCOUNT=`java -jar $HSQLDB_HOME/lib/hsqldb.jar --sql '
            select count(*) from usertbl
        ' urlid` || {
            # Handle the SqlTool error
        }
        echo "There are $USERCOUNT users registered in the database."
        [ "$USECOUNT" -gt 3 ] && {   # If there are more than 3 users registered
            # Some conditional shell scripting

### SQL Files

Just give paths to sql text file(s) on the command line after the urlid.

Often, you will want to redirect output to a file, like

    java -jar $HSQLDB_HOME/lib/hsqldb.jar sql... > /tmp/log.sql 2>&1

(Skip the "2>&1" if you're on Windows).

You can also execute SQL files from an interactive session with the "\i"' Special Command, but be aware that the default behavior in an interactive session is to continue upon errors. If the SQL file was written without any concern for error handling, then the file will continue to execute after errors occur. You could run `\c false` before `\i filename`, but then your SqlTool session will exit if an error is encountered in the SQL file. If you have an SQL file without error handling, and you want to abort that file when an error occurs, but not exit SqlTool, the easiest way to accomplish this is usually to add `\c false` to the top of the script.

If you specify multiple SQL files on the command-line, the default behavior is to exit SqlTool if any of the SQL files encounters an error.

SQL files themselves have ultimate control over error handling. Regardless of what command-line options are set, or what commands you give interactively, if a SQL file gives error handling statements, they will take precedence.

You can also use \i in SQL files. This results in nested SQL files.

You can use the following SQL file, `sample.sql`, which resides in the `src/org/hsqldb/sample` directory of your HSQLDB distribution. It contains SQL as well as Special Commands making good use of most of the Special Commands documented below.

    /*
        $Id: sample.sql,v 1.5 2005/05/02 15:07:27 unsaved Exp $
        Examplifies use of SqlTool.
        PCTASK Table creation
    */

    /* Ignore error for these two statements */
    \c true
    DROP TABLE pctasklist;
    DROP TABLE pctask;
    \c false

    \p Creating table pctask
    CREATE TABLE pctask (
        id integer identity,
        name varchar(40),
        description varchar,
        url varchar,
        UNIQUE (name)
    );

    \p Creating table pctasklist
    CREATE TABLE pctasklist (
        id integer identity,
        host varchar(20) not null,
        tasksequence int not null,
        pctask integer,
        assigndate timestamp default current_timestamp,
        completedate timestamp,
        show bit default true,
        FOREIGN KEY (pctask) REFERENCES pctask,
        UNIQUE (host, tasksequence)
    );

    \p Granting privileges
    GRANT select ON pctask TO public;
    GRANT all ON pctask TO tomcat;
    GRANT select ON pctasklist TO public;
    GRANT all ON pctasklist TO tomcat;

    \p Inserting test records
    INSERT INTO pctask (name, description, url) VALUES (
        'task one', 'Description for task 1', 'http://cnn.com');
    INSERT INTO pctasklist (host, tasksequence, pctask) VALUES (
        'admc-masq', 101, SELECT id FROM pctask WHERE name = 'task one');

    commit;

You can execute this SQL file with a Memory Only database with a command like

        java -jar $HSQLDB_HOME/lib/hsqldb.jar  --sql '
            create user tomcat password "x"
        ' mem path/to/hsqldb/src/org/hsqldb/sample/sample.sql

(The `--sql "create..."` arguments create an account which the script uses).

### Piping and shell scripting

You can of course, redirect output from SqlTool to a file or another program.

        java -jar $HSQLDB_HOME/lib/hsqldb.jar urlid file.sql > file.txt 2>&1

        java -jar $HSQLDB_HOME/lib/hsqldb.jar urlid file.sql 2>&1 | someprogram...

You can type commands in to SqlTool while being in non-interactive mode by supplying "-" as the file name. This is a good way to test how SqlTool will behave when processing your SQL files.

            java -jar $HSQLDB_HOME/lib/hsqldb.jar urlid -

This is how you have SqlTool read its input from another program:

Example 8.5. Piping input into SqlTool

            echo "Some SQL commands with '$VARIABLES';" |
            java -jar $HSQLDB_HOME/lib/hsqldb.jar urlid -

Make sure that you also read the Giving SQL on the Command Line section. The `--sql` switch is a great facility to use with shell scripts.

### Optimally Compatible SQL Files

If you want your SQL scripts optimally compatible among other SQL tools, then don't use any Special or PL Commands. SqlTool has default behavior which I think is far superior to the other SQL tools, but you will have to disable these defaults in order to have optimally compatible behavior.

These switches provide compatibilty at the cost of poor control and error detection.

- --continueOnErr

  The output will still contain error messages about everything that SqlTool doesn't like (malformatted commands, SQL command failures, empty SQL commands), but SqlTool will continue to run. Errors will not cause rollbacks (but that won't matter because of the following setting).

- --autoCommit

You don't have to worry about accidental expansion of PL variables, since SqlTool will never expand PL variables if you don't set any variables on the command line, or give any "* " PL commands. (And you could not have "* " commands in a compatible SQL file).

### Comments

SQL comments of the form `/*...*/` must begin where a (SQL/Special/Buffer/PL) Command could begin, and they end with the very first "*/" (regardless of quotes, nesting, etc. You may have as many blank lines as you want inside of a comment.

Example 8.6. Valid comment example

        SELECT count(*) FROM atable;
        /* Lots of
         comments interspersed among
         several lines */   SELECT count(*)
        FROM btable;

Notice that a command can start immediate after the comment ends.

Example 8.7. Invalid comment example

        SELECT count(*) FROM
        /* atable */
        btable;

This comment is invalid because you could not start another command at the comment location (because it is within an SQL Statement).

You can try using `/*...*/` in other locations, and `--` style SQL comments, but SqlTool will not treat them as comments. If they occur within an SQL Statment, SqlTool will pass them to the database engine, and the DB engine will determine whether to parse them as comments.

### Special Commands and Buffer Commands in SQL Files

Don't use Buffer Commands in your sql files, because they won't work. Buffer Commands are for interactive use only. (But, see the Raw Mode section for an exception).

\q [abort message]

  Be aware that the \q command will cause SqlTool to completely exit. If a script `x.sql` has a \q command in it, then it doesn't matter if the script is executed like

          java -jar .../hsqldb.jar urlid a.sql x.sql z.sql

  or if you use \i to read it in interactively, or if another SQL file uses \i to nest it. If \q is encountered, SqlTool will quit. See the SqlTool Procedural Language section for commands to abort an SQL file (or even parts of an SQL file) without causing SqlTool to exit.

  \q takes an optional argument, which is an abort message. If you give an abort message, the message is displayed to the user and SqlTool will exit with a failure status. If you give no abort message, then SqlTool will exit quietly with successful status.

\p [text to print]
  Print the given string to stdout. Just give "\p" alone to print a blank line.
\i /path/to/file.sql
  Include another SQL file at this location. You can use this to nest SQL files. For database installation scripts I often have a master SQL file which includes all of the other SQL files in the correct sequence. Be aware that the current continue-upon-error behavior will apply to included files until such point as the SQL file runs its own error handling commands.
\H

  Toggle HTML output mode. If you redirect output to a file, this can make a long session log much easier to view. This will HTML-ify the entire session. For example,

      java -jar $HSQLDB_HOME/lib/hsqldb.jar urlid filepath1.sql... > /tmp/log.html 2>&1

  (See the Generating Text or HTML Reports section about how to easily store just the query output to file.)
\a [true|false]
  This turns on and off SQL transaction autocommits. Auto-commit defaults to false, but you can change that behavior by using the `--autoCommit` command-line switch.
\c [true|false]

  A "true" setting tells SqlTool to Continue when errors are encountered. The current transaction will not be rolled back upon SQL errors, so if \c is true, then run the `ROLLCACK;` command yourself if that's what you want to happen. The default for interactive use is to continue upon error, but the default for non-interactive use is to abort upon error. You can override this behavior by using the `--continueOnErr` or the `--abortOnErr` command-line switch.

  With database setup scripts, I usually find it convenient to set "true" before dropping tables (so that things will continue if the tables aren't there), then set it back to false so that real errors are caught. `DROP TABLE tablename IF EXISTS;` is a more elegant, but less portable, way to accomplish the same thing.

  ### Tip

  It depends on what you want your SQL files to do, of course, but I usually want my SQL files to abort when an error is encountered, without necessarily killing the SqlTool session. If this is the behavior that you want, then put an explicit `\c false` at the top of your SQL file and turn on continue-upon-error only for sections where you really want to permit errors, or where you are using PL commands to handle errors manually. This will give the desired behavior whether your script is called by somebody interactively, from the SqlTool command-line, or included in another SQL file (i.e. nested).

  ### Important

  The default settings are usually best for people who don't want to put in any explicit \c or error handling code at all. If you run SQL files from the SqlTool command line, then any errors will cause SqlTool to roll back and abort immediately. If you run SqlTool interactively and invoke SQL files with \i commands, the scripts will continue to run upon errors (and will not roll back). This behavior was chosen because there are lots of SQL files out there that produce errors which can be ignored; but we don't want to ignore errors that a user won't see. I reiterate that any and all of this behavior can (and often should) be changed by Special Commands run in your interactive shell or in the SQL files. Only you know whether errors in your SQL files can safely be ignored.

### Automation

SqlTool is ideal for mission-critical automation because, unlike other SQL tools, SqlTool returns a dependable exit status and gives you control over error handling and SQL transactions. Autocommit is off by default, so you can build a completely dependable solution by intelligently using \c commands (Continue upon Errors) and commit statements, and by verifying exit statuses.

Using the SqlTool Procedural Language, you have ultimate control over program flow, and you can use variables for database input and output as well as for many other purposes. See the SqlTool Procedural Language section.

### Getting Interactive Functionality with SQL Files

Some script developers may run into cases where they want to run with sql files but they alwo want SqlTool's interactive behavior. For example, they may want to do command recall in the sql file, or they may want to log SqlTool's command-line prompts (which are not printed in non-interactive mode). In this case, do not give the sql file(s) as an argument to SqlTool, but pipe them in instead, like

    java -jar $HSQLDB_HOME/lib/hsqldb.jar urlid < filepath1.sql > /tmp/log.html 2>&1

or

    cat filepath1.sql... |
    java -jar $HSQLDB_HOME/lib/hsqldb.jar urlid > /tmp/log.html 2>&1

### Character Encoding

SqlTool defaults to the US-ASCII character set (for reading). You can use another character set by setting the system property sqlfile.charset, like

    java -Dsqlfile.charset=UTF-8 -jar $HSQLDB_HOME/lib/hsqldb.jar urlid file.sql...

You can also set this per urlid in the SqlTool configuration file. See the RC File Authentication Setup section about that.

## Generating Text or HTML Reports

This section is about making a file containing the output of database queries. You can generate reports by using operating system facilities such as redirection, tee, and cutting and pasting. But it is much easier to use the "\o" and "\H" special commands.

Procedure 8.5. Writing query output to an external file

1. By default, everthing will be done in plain text. If you want your report to be in HTML format, then give the special command `\H`. If you do so, you will probably want to use filenames with an suffix of ".html" or ".htm" instead of ".txt" in the next step.

2. Run the command `\o path/to/reportfile.txt`. From this point on, output from your queries will be appended to the specified file. (I.e. another copy of the output is generated.) This way you can continue to monitor or use output as usual as the report is generated.

3. When you want SqlTool to stop writing to the file, run `\o` (or just quit SqlTool if you have no other work to do).

4. If you turned on HTML mode with `\H` before, you can run `\H` again to turn it back off, if you wish.

It is not just the output of "SELECT" statements that will make it into the report file, but

Kinds of output that get teed to \o files

- Output of SELECT statements.
- Output of all "\d" Special Commands. (I.e., "\dt", "\dv", etc., and "\d OBJECTNAME").
- Output of "\p" Special Commands. You will want to use this to add titles, and perhaps spacing, for the output of individual queries.

Other output will go to your screen or stdout, but will not make it into the report file. Be aware that no error messages will go into the report file. If SqlTool is run non-interactively (including if you give any SQL file(s) on the command line), SqlTool will abort with an error status if errors are encountered. The right way to handle errors is to check the SqlTool exit status. (The described error-handling behavior can be modified with SqlTool command-line switches and Special Commands).

### Warning

Remember that \o appends to the named file. If you want a new file, then use a new file name or remove the targe file ahead of time.

### Tip

So that I don't end up with a bunch of junk in my report file, I usually leave \o off while I perfect my SQL. With \o off, I perfect the SQL query until it produces on my screen exactly what I want saved to file. At this point I turn on \o and run ":;" to repeat the last SQL command. If I have several complex queries to run, I turn \o off and repeat until I'm finished. (Every time you turn \o on, it will append to the file, just like we need).

Usually it doesn't come to mind that I need a wider screen until a query produces lines that are too long. In this case, stretch your window and repeat the last command with the ":;" Buffer Command.

## SqlTool Procedural Language

### Aka PL

Most importantly, run `SqlTool` interactively and give the "*?" command to see what PL commands are available to you.

PL variables will only be expanded after you run a PL command (or set variable(s) from the command-line). We only want to turn on variable expansion if the user wants variable expansion. People who don't use PL don't have to worry about strings getting accidentally expanded.

All other PL commands imply the "*" command, so you only need to use the "*" statement if your script uses PL variables and it is possible that no variables may be set before-hand (and no PL commands have been run previously). In this case, without "*", your script would silently use a literal value like "*{x}" instead of trying to expand it. With a preceding "*" command, PL will notice that the variable `x` has not been set and will generate an error. (If x had been set here will be no issue because setting a variable automatically turns on PL variable expansion).

PL is also used to upload and download column values to/from local ASCII files, analogously to the special \b commands for binary files. This is explained above in the Interactive Essential PL Command section above.

### Variables

- Use the `* list` command to list some or all variables; or `* listvalue` to also see the values.
- You can set variables using the `* VARNAME = value` command.
- You can also set variables using the `--setvar` command-line switch. I give a very brief but useful example of this below.
- Variables are always expanded in SQL, Special, and PL commands if they are written like `*{VARNAME}` (assuming that a PL command has been run previously). Your SQL scripts can give good feedback by echoing the value of variables with the "\p" special command.

- A variable written like `/VARNAME` is expanded if it begins an SQL Statement. This usage is called PL Aliasing. See the PL Aliases section below.

- Variables are normally written like `*VARNAME` in logical expressions to prevent them from being evaluated too early. See below about logical expressions.

- You can't do math with expression variables, but you can get functionality like the traditional `for (i = 0; i < x; i++)` by appending to a variable and testing the string length, like

          * while (*i < ${x})
              * i = *{i}.

  `i` will be a growing line of dots.

- Variable names must not contain white space, or the characters "}" or "=".

### PL Aliases

PL Aliasing just means the use of a PL variable as the first thing in an SQL statement, with the shortcut notation `/VARNAME`.

`/VARNAME` must be followed by whitespace or terminate the Statement, in order for SqlFile to tell where the variable name ends.

### Note

Note that PL aliases are a very different thing from SQL aliases or HSQLDB aliases, which are features of databases, not SqlFile.

If the value of a variable is an entire SQL command, you generally do not want to include the terminating ";" in the value. There is an example of this above.

PL aliasing may only be used for SQL statements. You can define variables for everything in a Special or PL Command, except for the very first character ("\" or "*"). Therefore, you can use variables other than alias variables in Special and PL Commands. Here is a hyperbolically impractical example to show the extent to which PL variables can be used in Special commands even though you can not use them as PL aliases.

            sql> * qq = p Hello Butch
            sql> \*{qq} done now
            Hello Butch done now

(Note that the \* here is not the special command "\*", but is the special command "\p" because "*{qq}" resolves to "p").

Here is a short SQL file that gives the specified user write permissions on some application tables.

Example 8.8. Simple SQL file using PL

        /*
           grantwrite.sql

           Run SqlTool like this:
               java -jar path/to/hsqldb.jar -setvar USER=debbie grantwrite.sql
         */

        /* Explicitly turn on PL variable expansion, in case no variables have
           been set yet.  (Only the case if user did not set USER).
        */
        *

        GRANT all ON book TO *{USER};
        GRANT all ON category TO *{USER};

Note that this script will work for any (existing) user just by supplying a different user name on the command-line. I.e., no need to modify the tested and proven script. There is no need for a `commit` statement in this SQL file since no DML is done. If the script is accidentally run without setting the USER variable, SqlTool will give a very clear notificaton of that.

The purpose of the plain "*" command is just so that the *{USER} variables will be expanded. (This would not be necessary if the USER variable, or any other variable, were set, but we don't want to depend upon that).

### Logical Expressions

Logical expressions occur only inside of logical expression parentheses in PL statements. For example, `if (*var1 > astring)` and `while (*checkvar)`. (The parentheses after "foreach" do not enclose a logical expression, they just enclose a list).

There is a critical difference between `*{VARNAME}` and `*VARNAME` inside logical expressions. `*{VARNAME}` is expanded one time when the parser first encounters the logical expression. `*VARNAME` is re-expanded every time that the expression is evaluated. So, you would never want to code `* while (*{X} < 5)` because the statement will always be true or always be false. (I.e. the following block will loop infinitely or will never run).

Don't use quotes or whitespace of any kind in `*{VARNAME}` variables in expressions. (They would expand and then the expression would most likely no longer be a valid expression as listed in the table below). Quotes and whitespace are fine in `*VARNAME` variables, but it is the entire value that will be used in evaluations, regardless of whether quotes match up, etc. I.e. quotes and whitespace are not special to the token evaluator.

Logical Operators

TOKEN
  The token may be a literal, a `*{VARNAME}` which is expanded early, or a *VARNAME which is expanded late. (You usually do not want to use `*{VARNAME}` in logical expressions). False if the token is not set, empty, or "0". True otherwise.
TOKEN1 == TOKEN2
  True if the two tokens are equivalent "strings".
TOKEN1 <> TOKEN2
  Ditto.
TOKEN1 >< TOKEN2
  Ditto.
TOKEN1 > TOKEN2
  True if the TOKEN1 string is longer than TOKEN2 or is the same length but is greater according to a string sort.
TOKEN1 < TOKEN2
  Similarly to TOKEN1 > TOKEN2.
! LOGICAL_EXPRESSION
  Logical negation of any of the expressions listed above.

*VARNAMEs in logical expressions, where the VARNAME variable is not set, evaluate to an empty string. Therefore `(*UNSETVAR = 0)` would be false, even though `(*UNSETVAR)` by itself is false and `(0)` by itself is false.

When developing scripts, you definitely use SqlTool interactively to verify that SqlTool evaluates logical expressions as you expect. Just run `* if` commands that print something (i.e. \p) if the test expression is true.

### Flow Control

Flow control works by conditionally executing blocks of Commands according to conditions specified by logical expressions.

The conditionally executed blocks are called PL Blocks. These PL Blocks always occur between a PL flow control statement (like `* foreach, *while, * if`) and a corresponding `* end` PL Command (like `* end foreach`).

### Caution

Be aware that the PL block reader is ignorant about SQL statements and comments when looking for the end of the block. It just looks for lines beginning with some specific PL commands. Therefore, if you put a comment line before a PL statement, or if a line of a multi-line SQL statement has a line beginning with a PL command, things may break.

I am not saying that you shouldn't use PL commands or SQL commands inside of PL blocks-- you definitely should! I'm saying that in PL blocks you should not have lines inside of SQL statments or comments which could be mistaken for PL commands. (Especially, "commenting out" PL end statements will not work if you leave `* end` at the beginning of the line).

(This limitation will very likely be removed in a future version of SqlTool).

The values of control variables for foreach and while PL blocks will change as expected.

There are `* break` and `* continue`, which work as any shell scripter would expect them to. The `* break` command can also be used to quit the current SQL file without triggering any error processing. (I.e. processing will continue with the next line in the including SQL file or interactive session, or with the next SQL file if you supplied multiple on the command-line).

Below is an example SQL File that shows how to use most PL features. If you have a question about how to use a particular PL feature, check this example before asking for help. This file resides in the `src/org/hsqldb/sample` directory with the name `pl.sql`. Definitely give it a run, like

    java -jar $HSQLDB_HOME/lib/hsqldb.jar mem $HSQLDB_HOME/src/org/hsqldb/sample/pl.jar

Example 8.9. SQL File showing use of most PL features

    /*
        $Id: pl.sql,v 1.4 2005/05/02 15:07:26 unsaved Exp $
        SQL File to illustrate the use of SqlTool PL features.
        Invoke like
            java -jar .../hsqldb.jar .../pl.sql mem
                                                             -- blaine
    */

    * if (! *MYTABLE)
        \p MYTABLE variable not set!
        /* You could use \q to Quit SqlTool, but it's often better to just
           break out of the current SQL file.
           If people invoke your script from SqlTool interactively (with
           \i yourscriptname.sql) any \q will kill their SqlTool session. */
        \p Use arguments "--setvar MYTABLE=mytablename" for SqlTool
        * break
    * end if

    /* Turning on Continue-upon-errors so that we can check for errors ourselves.*/
    \c true

    \p
    \p Loading up a table named '*{MYTABLE}'...

    /* This sets the PL variable 'retval' to the return status of the following
       SQL command */
    * retval ~
    CREATE TABLE *{MYTABLE} (
        i int,
        s varchar
    );
    \p CREATE status is *{retval}
    \p

    /* Validate our return status.  In logical expressions, unset variables like
       *unsetvar are equivalent to empty string, which is not equal to 0
       (though both do evaluate to false on their own, i.e. (*retval) is false
       and (0) is false */
    * if (*retval != 0)
        \p Our CREATE TABLE command failed.
        * break
    * end if

    /* Default Continue-on-error behavior is what you usually want */
    \c false
    \p

    /* Insert data with a foreach loop.
       These values could be from a read of another table or from variables
       set on the command line like
    */
    \p Inserting some data int our new table (you should see 3 row update messages)
    * foreach VALUE (12 22 24 15)
        * if (*VALUE > 23)
            \p Skipping *{VALUE} because it is greater than 23
            * continue
            \p YOU WILL NEVER SEE THIS LINE, because we just 'continued'.
        * end if
        INSERT INTO *{MYTABLE} VALUES (*{VALUE}, 'String of *{VALUE}');
    * end foreach
    \p

    * themax ~
    /* Can put Special Commands and comments between "* VARNAME ~" and the target
       SQL statement. */
    \p We're saving the max value for later.  You'll still see query output here:
    SELECT MAX(i) FROM *{MYTABLE};

    /* This is usually unnecessary because if the SELECT failed, retval would
       be undefined and the following print statement would make SqlTool exit with
       a failure status */
    * if (! *themax)
        \p Failed to get the max value.
        /* It's possible that the query succeeded but themax is "0".
           You can check for that if you need to. */
        * break
        \p YOU WILL NEVER SEE THIS LINE, because we just 'broke'.
    * end if

    \p
    \p ##############################################################
    \p The results of our work:
    SELECT * FROM *{MYTABLE};
    \p MAX value is *{themax}

    \p
    \p Everything worked.

## Chunking

We hereby call the ability to transmit multiple SQL commands to the database in one transmission chunking. Unless you are in Raw mode, SqlTool only transmits commands to the database engine when it reads in a ";" at the end of a line of an SQL command. Therefore, you normally want to end each and every SQL command with ";" at the end of a line. This is because the database can only send one status reply to each JDBC transmission. So, while you could run

        SELECT * FROM t1; SELECT * FROM t2;

SqlTool can only display the results from the last query. This is a limitation of the client/server nature of JDBC, and applies to any JDBC client. There are, however, situations where you don't need immediate feedback from every SQL command. For example,

Example 8.10. Single-line chunking example

        INSERT INTO t1 VALUES(0); SELECT * FROM t1;

It's useful because the output of the second SQL command will tell you whether the first SQL command succeeded. So, you won't miss the status output from the first command.

### Why?

The first general reason to chunk SQL commands is performance. For standalone databases, the most common performance bottleneck is network latency. Chunking SQL commands can dramatically reduce network traffic.

The second general reason to chunk SQL commands is if your database requires you to send multiple commands in one transmission. This is often the case when you need to tell the database the SQL or PL/SQL commands that comprise a stored procedure, function, trigger, etc.

### How?

The most simple way is enter as many SQL commands as you want, but just do not end a line with ";" until you want the chunk to transmit.

Example 8.11. Multi-line chunking example

        INSERT INTO t1 VALUES (1)
        ; INSERT INTO t1 VALUES (2)
        ; SELECT * FROM t1;

If you list your command history with \s, you will see that all 3 SQL commands in 3 lines are in one SqlTool command. You can recall this SqlTool command from history to re-execute all three SQL commands.

The other method is by using Raw Mode. Go to the Raw Mode section to see how. You can enter any text at all, exactly how you want it to be sent to the database engine. Therefore, in addition to chunking SQL commands, you can give commands for non-SQL extensions to the database. For example, you could enter JavaScript code to be used in a stored procedure.

## Raw Mode

You begin raw mode by issuing the Special Command "\.". You can then enter as much text in any format you want. When you are finished, enter a line consisting of only ".". If you are running SqlTool interactively, you'll notice that your prompt will be the continuation prompt until you enter the "." line.

When you terminate raw entry with the "\." line, the command does not execute, it just goes into the command buffer. If running interactively, you can look at the buffer with the ":l" Buffer Command. What you will normally want to do is to enter the Buffer Command ":;" to transmit the buffer to the database engine.

Example 8.12. Raw Mode example

        sql> \.
        Enter RAW SQL.  No \, :, * commands.  End with a line containing only ".":
        raw> line one;
          +> line two;
          +> line three;
          +> .
        Raw SQL chunk moved into buffer.  Run ":;" to execute the chunk.
        sql> :;
        Executing command from buffer:
        line one;
        line two;
        line three;

        SQL Error at 'stdin' line 13:
        "line one;
        line two;
        line three;"
        Unexpected token: LINE in statement [line]
        sql>

The error message "Unexpected token: LINE in statement [line]" comes from the database engine, not SqlTool. All three lines were transmitted to the database engine.

Buffer Commands are generally unavailable when runninb SqlTool interactively. However, the command ":;", and the command buffer have been enabled for non-interactive use, because they are required for using raw mode, and it is definitely useful to be able to use raw mode in SQL files.

## PL/SQL

### Note

PL/SQL is not the same as PL. PL is the procedural language of SqlFile and is independent of your back-end database. PL commands always begin with *. PL/SQL is processed on the server side and you can only use it of your database supports it. You can not intermix PL and PL/SQL (except for setting a PL variable to the output of PL/SQL execution), because when you enter PL/SQL to SqlTool that input is not processed by SqlFile.

Use Raw Mode to send PL/SQL code blocks to the database engine. You do not need to enter the "\." command to enter raw mode. Just begin a new SqlTool command line with "DECLARE" or "BEGIN", and SqlTool will automatically put you into raw mode. See the Raw Mode section for details.

The following sample SQL file resides at `src/org/hsqldb/sample/plsql.sql` in your HSQLDB distribution. This script will only work if your database engine supports standard PL/SQL, if you have permission to create the table "T1" in the default schema, and if that object does not already exist.

Example 8.13. PL/SQL Example

    /*
     * $Id: plsql.sql,v 1.3 2005/05/02 15:09:11 unsaved Exp $
     *
     * This example is copied from the "Simple Programs in PL/SQL"
     * example by Yu-May Chang, Jeff Ullman, Prof. Jennifer Widom at
     * the Standord University Database Group's page
     * http://www-db.stanford.edu/~ullman/fcdb/oracle/or-plsql.html .
     * I have only removed some blank lines (because you can't use blank
     * lines inside of SQL commands in non-raw mode SqlTool when running
     * it interactively); and, at the bottom I have  replaced the
     * client-specific, non-standard command "run;" with SqlTool's
     * corresponding command ":;" and added a plain SQL SELECT command
     * to show whether the PL/SQL code worked.  - Blaine
     */

    CREATE TABLE T1(
        e INTEGER,
        f INTEGER
    );

    DELETE FROM T1;

    INSERT INTO T1 VALUES(1, 3);

    INSERT INTO T1 VALUES(2, 4);

    /* Above is plain SQL; below is the PL/SQL program. */
    DECLARE

        a NUMBER;

        b NUMBER;

    BEGIN

        SELECT e,f INTO a,b FROM T1 WHERE e>1;

        INSERT INTO T1 VALUES(b,a);

    END;

    .

    /**************************************************************************/
    /* Remaining SqlTool-specific code added by Blaine Simpson of the
     * HSQLDB Development Group.
     */

    :;

    /* This should show 3 rows, one containing values 4 and 2 (in this order)...*/
    SELECT * FROM t1;

Note that, inside of raw mode, you can use any kind of formatting you want: Whatever you enter-- blank lines, comments, everything-- will be transmitted to the database engine.

## Using hsqltool.jar and hsqldbutil.jar

This section is only for those users who want to use SqlTool but without the overhead of hsqldb.jar.

If you do not need to directly use JDBC URLs like `jdbc:hsqldb:mem:` + something, `jdbc:hsqldb:file:` + something, or `jdbc:hsqldb:res:` + something, then you can use `hsqltool.jar` in place of the much larger `hsqldb.jar` file. `hsqltool.jar` will work for all JDBC databases other than HSQLDB Memory-only and In-process databases (the latter are fine if you access them via a HSQLB Server or WebServer). You will have to supply the JDBC driver for non-HSQLDB URLs, of course.

`hsqltool.jar` includes the HSQLDB JDBC driver. If you do not need to connect to HSQLDB databases at all, then `hsqldbutil.jar` is what you need. `hsqldbutil.jar` contains everything you need to run `SqlTool` and `DatabaseManagerSwing` against non-HSQLDB databases... well, besides the JDBC drivers for the target databases.

The HSQLDB distribution doesn't "come with" a pre-built `hsqltool.jar` and `hsqldbutil.jar` files. You should build the hsqltool or hsqldbutil target, as explained in the Building HSQLDB appendix.

If you are using the HSQLDB JDBC driver (i.e., you're connecting up to a URL like jdbc:hsqldb:hsql + something or jdbc:hsqldb:http + something), you run SqlTool exactly as with hsqldb.jar except you use the file path to your new jar file instead of the path to `hsqldb.jar`.

If you are using a non-HSQLDB JDBC driver, follow the instructions at the end of the The Bare Minimum section, but use your new file in place of `hsqldb.jar`.

## Character-Separated-Value Imports and Exports

### Note

These features were added for version 1.8.0.3 of HSQLDB.

### Note

This feature is independent of HSQLDB Text Tables, a server-side feature of HSQLDB. It makes no difference to SqlTool whether the source or target table of your export/import is a memory, cache, or text table. Indeed, like all features of SqlTool, it works fine with other JDBC databases. It works great, for example to migrate data from a table of one type to a table of another type, or to another schema, or to another database instance, or to another database system.

Because of common usage of the term, I call this feature CSV imports and exports, even though the delimiters are not constrained to single characters, but may be any String. Use the `\x` command to eXport a table to a CSV file, and the `\m` command to iMport a CSV file into a pre-existing table.

Just as the delimiter capability is more general than traditional CSV delimiters, the export function is also more general than just a table data exporter. Besides the trivial generalization that you may specify a view or other virtual table name in place of a table name, you can alternatively export the output of any query which produces normal text output. A benefit to this approach is that it allows you to export only some columns of a table, and to specify a WHERE clause to narrow down the rows to be exported (or perform any other SQL transformation, mapping, join, etc.). One specific use for this would be to exclude columns of binary data (which can be exported by other means, such as a PL loop to store binary values to files with the \bd command).

Note that the import command will not create a new table. This is because of the impossibility of guessing appropriate types and constraints based only on column names and a data sampling (which is all that a CSV-importer has access to). Therefore, if you wish to populate a new table, create the table before running the import. The import file does not need to have data for all columns of a table. The only required columns are those required by non-null and FK constraints. One specific reason to omit columns is if you want values of some columns to be created automatically by column DEFAULT settings, triggers, HSQLDB identity sequences, etc. Another reason would be to skip binary columns.

### Simple CSV exports and imports using default settings

Even if you need to change delimiters, table names, or file names from the defaults, I suggest that you run one export and import with default settings as a practice run. A memory-only HSQLDB instance is ideal for test runs like this.

This command exports the table `icf.projects` to the file `projects.csv` in the current directory (where you invoked SqlTool from). By default, the output file name will be the specified source table name plus the extension `.csv`.

Example 8.14. CSV Export Example

        SET SCHEMA icf;
        \x projects

We could also have run `\x icf.projects` (which would have created a file named `icf.projects.csv`) instead of changing the session schema. In this example we have chosen to make the export file name independent of the schema to facilitate importing it into a different schema.

Take a look at the output file. Notice that the first line consists of column names, not data. This line is present because it will be needed if the file is to used for a CSV import. Notice the following characterstics about the export data. The column delimiter is the pipe character "|". The record delimiter is the default line delimiter character(s) for your operating system. The string used to represent database `NULL`s is `[null]`. See the next section for how to change these from their default values.

This command imports the data from the file `projects.csv` in the current directory (where you invoked SqlTool from) into the table `newschema.projects`. By default, the output table name will be the input filename after removing optional leading directory and trailing final extension.

Example 8.15. CSV Import Example

        SET SCHEMA newschema;
        \m projects.csv

If the CSV file was named with the target schema, you would have skipped the `SET SCHEMA` command, like `\m newschema.projects.csv`.

### Specifying queries, delimiters, file names, table names, columns

The header line in the CSV file is required at this time. (If there is user demand, it can be made optional for exporting, but it will remain required for importing).

Your export will fail if the column or record delimiter, or the null representation value occurs in the data being exported. You change these values by setting the PL variables `*CSV_COL_DELIM`, `*CSV_ROW_DELIM`, `*CSV_NULL_REP`. Notice that the asterisk is part of the variable names, to indicate that these variables are used by SqlTool internally. You can use the escape sequences \n, \r, and \t in the usual manner. For example, to change the column delimiter to the tab character, you would give the command

        * *CSV_COL_DELIM = \t

For imports, you must always specify the source CSV file path. If you want to export to a different file than one in the current directory named according to the source table, set the PL variable `*CSV_FILEPATH`, like

        * *CSV_FILEPATH = /tmp/dtbl.csv

For exports, you must always specify the source table name or query. If you want to import to a table other than that derived from the input CSV file name, set the PL variable `*CSV_TABLENAME`. The table name may contain a schema name prefix.

At this time, you must import all columns that have data in the CSV file. If there is demand to specify an optional list of columns to import, I'll gladly add that feature.

You can specify a query instead of a tablename with the \x command in order to filter or transform data from a table or view, or to export the output of a join, etc. You must set the PL variable `*CSV_FILEPATH`, as explained above (since there is no table name from which to automatically map a file name).

Example 8.16. CSV Export of an Arbitrary SELECT Statement

        * *CSV_FILEPATH = outfile.txt
        \x SELECT entrydate, 2 * aval "Double aval", modtime from bs.dtbl

Note that I specified the column label alias "Double aval" so that the label for that column in the CSV file header will not be blank.

Chapter 7. TLS |  | Chapter 9. SQL Syntax