Class | Sequel::Schema::Generator
In: | lib/sequel/database/schema_generator.rb lib/sequel/extensions/schema_dumper.rb
Parent: | Object

Schema::Generator is an internal class that the user is not expected to instantiate directly. Instances are created by Database#create_table. It is used to specify table creation parameters. It takes a Database object and a block of column/index/constraint specifications, and gives the Database a table description, which the database uses to create a table.

Schema::Generator has some methods but also includes method_missing, allowing users to specify column type as a method instead of using the column method, which makes for a nicer DSL.

For more information on Sequel‘s support for schema modification, see the "Migrations and Schema Modification" guide.

### Methods

add_type_method check column constraint dump_columns dump_constraints dump_indexes foreign_key full_text_index has_column? index method_missing new primary_key primary_key_name spatial_index unique

### Constants

GENERIC_TYPES | = | [String, Integer, Fixnum, Bignum, Float, Numeric, BigDecimal, Date, DateTime, Time, File, TrueClass, FalseClass] |  | Classes specifying generic types that Sequel will convert to database-specific types.

### Attributes

columns | [R] | Return the columns created by this generator
constraints | [R] | Return the constraints created by this generator
indexes | [R] | Return the indexes created by this generator

### Public Class methods

add_type_method(*types)

Add a method for each of the given types that creates a column with that type as a constant. Types given should either already be constants/classes or a capitalized string/symbol with the same name as a constant/class.

[Source]

        # File lib/sequel/database/schema_generator.rb, line 47
    47:       def self.add_type_method(*types)
    48:         types.each do |type|
    49:           class_eval("def #{type}(name, opts={}); column(name, #{type}, opts); end", __FILE__, __LINE__)
    50:         end
    51:       end

new(db, &block)

Set the database in which to create the table, and evaluate the block in the context of this object.

[Source]

        # File lib/sequel/database/schema_generator.rb, line 33
    33:       def initialize(db, &block)
    34:         @db = db
    35:         @columns = []
    36:         @indexes = []
    37:         @constraints = []
    38:         @primary_key = nil
    39:         instance_eval(&block) if block
    40:         @columns.unshift(@primary_key) if @primary_key && !has_column?(primary_key_name)
    41:       end

### Public Instance methods

check(*args, &block)

Add a unnamed constraint to the DDL, specified by the given block or args.

[Source]

        # File lib/sequel/database/schema_generator.rb, line 55
    55:       def check(*args, &block)
    56:         constraint(nil, *args, &block)
    57:       end

column(name, type, opts = {})

Add a column with the given name, type, and opts to the DDL.

You can also create columns via method missing, so the following are equivalent:

      column :number, :integer
      integer :number

The following options are supported:

- :default - The default value for the column.
- :index - Create an index on this column.
- :key - For foreign key columns, the column in the associated table that this column references. Unnecessary if this column references the primary key of the associated table.
- :null - Mark the column as allowing NULL values (if true), or not allowing NULL values (if false). If unspecified, will default to whatever the database default is.
- :on_delete - Specify the behavior of this column when being deleted. See Schema::SQL#on_delete_clause for options.
- :on_update - Specify the behavior of this column when being updated. See Schema::SQL#on_delete_clause for options.
- :size - The size of the column, generally used with string columns to specify the maximum number of characters the column will hold. An array of two integers can be provided to set the size and the precision, respectively, of decimal columns.
- :unique - Mark the column as unique, generally has the same effect as creating a unique index on the column.
- :unsigned - Make the column type unsigned, only useful for integer columns.
- :deferrable - This ensure Referential Integrity will work even if reference table will use for its foreign key a value that does not exists(yet) on referenced table. Basically it adds DEFERRABLE INITIALLY DEFERRED on key creation.

[Source]

        # File lib/sequel/database/schema_generator.rb, line 93
    93:       def column(name, type, opts = {})
    94:         columns << {:name => name, :type => type}.merge(opts)
    95:         index(name) if opts[:index]
    96:       end

constraint(name, *args, &block)

Adds a named constraint (or unnamed if name is nil) to the DDL, with the given block or args.

[Source]

         # File lib/sequel/database/schema_generator.rb, line 100
    100:       def constraint(name, *args, &block)
    101:         constraints << {:name => name, :type => :check, :check => block || args}
    102:       end

dump_columns()

Dump this generator‘s columns to a string that could be evaled inside another instance to represent the same columns

[Source]

         # File lib/sequel/extensions/schema_dumper.rb, line 192
    192:       def dump_columns
    193:         strings = []
    194:         cols = columns.dup
    195:         if pkn = primary_key_name
    196:           cols.delete_if{|x| x[:name] == pkn}
    197:           pk = @primary_key.dup
    198:           pkname = pk.delete(:name)
    199:           @db.serial_primary_key_options.each{|k,v| pk.delete(k) if v == pk[k]}
    200:           strings << "primary_key #{pkname.inspect}#{opts_inspect(pk)}"
    201:         end
    202:         cols.each do |c|
    203:           c = c.dup
    204:           name = c.delete(:name)
    205:           type = c.delete(:type)
    206:           opts = opts_inspect(c)
    207:           strings << if type.is_a?(Class)
    208:             "#{type.name} #{name.inspect}#{opts}"
    209:           else
    210:             "column #{name.inspect}, #{type.inspect}#{opts}"
    211:           end
    212:         end
    213:         strings.join("\n")
    214:       end

dump_constraints()

Dump this generator‘s constraints to a string that could be evaled inside another instance to represent the same constraints

[Source]

         # File lib/sequel/extensions/schema_dumper.rb, line 218
    218:       def dump_constraints
    219:         cs = constraints.map do |c|
    220:           c = c.dup
    221:           type = c.delete(:type)
    222:           case type
    223:           when :check
    224:             raise(Error, "can't dump check/constraint specified with Proc") if c[:check].is_a?(Proc)
    225:             name = c.delete(:name)
    226:             if !name and c[:check].length == 1 and c[:check].first.is_a?(Hash)
    227:               "check #{c[:check].first.inspect[1...-1]}"
    228:             else
    229:               "#{name ? "constraint #{name.inspect}," : 'check'} #{c[:check].map{|x| x.inspect}.join(', ')}"
    230:             end
    231:           else
    232:             cols = c.delete(:columns)
    233:             "#{type} #{cols.inspect}#{opts_inspect(c)}"
    234:           end
    235:         end
    236:         cs.join("\n")
    237:       end

dump_indexes(options={})

Dump this generator‘s indexes to a string that could be evaled inside another instance to represent the same indexes. Options:

- :add_index - Use add_index instead of index, so the methods can be called outside of a generator but inside a migration. The value of this option should be the table name to use.
- :drop_index - Same as add_index, but create drop_index statements.
- :ignore_errors - Add the ignore_errors option to the outputted indexes

[Source]

         # File lib/sequel/extensions/schema_dumper.rb, line 246
    246:       def dump_indexes(options={})
    247:         is = indexes.map do |c|
    248:           c = c.dup
    249:           cols = c.delete(:columns)
    250:           if table = options[:add_index] || options[:drop_index]
    251:             "#{options[:drop_index] ? 'drop' : 'add'}_index #{table.inspect}, #{cols.inspect}#{', :ignore_errors=>true' if options[:ignore_errors]}#{opts_inspect(c)}"
    252:           else
    253:             "index #{cols.inspect}#{opts_inspect(c)}"
    254:           end
    255:         end
    256:         is.join("\n")
    257:       end

foreign_key(name, table=nil, opts = {})

Add a foreign key in the table that references another table to the DDL. See column for available options.

[Source]

         # File lib/sequel/database/schema_generator.rb, line 106
    106:       def foreign_key(name, table=nil, opts = {})
    107:         opts = case table
    108:         when Hash
    109:           table.merge(opts)
    110:         when Symbol
    111:           opts.merge(:table=>table)
    112:         when NilClass
    113:           opts
    114:         else
    115:           raise(Error, "The second argument to foreign_key should be a Hash, Symbol, or nil")
    116:         end
    117:         return composite_foreign_key(name, opts) if name.is_a?(Array)
    118:         column(name, Integer, opts)
    119:       end

full_text_index(columns, opts = {})

Add a full text index on the given columns to the DDL.

[Source]

         # File lib/sequel/database/schema_generator.rb, line 122
    122:       def full_text_index(columns, opts = {})
    123:         index(columns, opts.merge(:type => :full_text))
    124:       end

has_column?(name)

True if the DDL includes the creation of a column with the given name.

[Source]

         # File lib/sequel/database/schema_generator.rb, line 127
    127:       def has_column?(name)
    128:         columns.any?{|c| c[:name] == name}
    129:       end

index(columns, opts = {})

Add an index on the given column(s) with the given options to the DDL. The available options are:

- :type - The type of index to use (only supported by some databases)
- :unique - Make the index unique, so duplicate values are not allowed.
- :where - Create a partial index (only supported by some databases)

[Source]

         # File lib/sequel/database/schema_generator.rb, line 137
    137:       def index(columns, opts = {})
    138:         indexes << {:columns => Array(columns)}.merge(opts)
    139:       end

method_missing(type, name = nil, opts = {})

Add a column with the given type, name, and opts to the DDL. See column for available options.

[Source]

         # File lib/sequel/database/schema_generator.rb, line 143
    143:       def method_missing(type, name = nil, opts = {})
    144:         name ? column(name, type, opts) : super
    145:       end

primary_key(name, *args)

Add primary key information to the DDL. Takes between one and three arguments. The last one is an options hash as for Generator#column. The first one distinguishes two modes: an array of existing column names adds a composite primary key constraint. A single symbol adds a new column of that name and makes it the primary key. In that case the optional middle argument denotes the type.

Examples:

      primary_key(:id)
      primary_key(:zip_code, :null => false)
      primary_key([:street_number, :house_number])
      primary_key(:id, :string, :auto_increment => false)

[Source]

         # File lib/sequel/database/schema_generator.rb, line 159
    159:       def primary_key(name, *args)
    160:         return composite_primary_key(name, *args) if name.is_a?(Array)
    161:         @primary_key = @db.serial_primary_key_options.merge({:name => name})
    162:
    163:         if opts = args.pop
    164:           opts = {:type => opts} unless opts.is_a?(Hash)
    165:           if type = args.pop
    166:             opts.merge!(:type => type)
    167:           end
    168:           @primary_key.merge!(opts)
    169:         end
    170:         @primary_key
    171:       end

primary_key_name()

The name of the primary key for this table, if it has a primary key.

[Source]

         # File lib/sequel/database/schema_generator.rb, line 174
    174:       def primary_key_name
    175:         @primary_key[:name] if @primary_key
    176:       end

spatial_index(columns, opts = {})

Add a spatial index on the given columns to the DDL.

[Source]

         # File lib/sequel/database/schema_generator.rb, line 179
    179:       def spatial_index(columns, opts = {})
    180:         index(columns, opts.merge(:type => :spatial))
    181:       end

unique(columns, opts = {})

Add a unique constraint on the given columns to the DDL.

[Source]

         # File lib/sequel/database/schema_generator.rb, line 184
    184:       def unique(columns, opts = {})
    185:         constraints << {:type => :unique, :columns => Array(columns)}.merge(opts)
    186:       end

[Validate]