Module | Sequel::SQLite::DatasetMethods
In: | lib/sequel/adapters/shared/sqlite.rb

Instance methods for datasets that connect to an SQLite database

### Methods

complex_expression_sql constant_sql delete explain having quoted_identifier supports_intersect_except_all? supports_is_true? supports_multiple_column_in? supports_timestamp_timezones?

### Constants

SELECT_CLAUSE_METHODS | = | Dataset.clause_methods(:select, %w'distinct columns from join where group having compounds order limit')
CONSTANT_MAP | = | {:CURRENT_DATE=>"date(CURRENT_TIMESTAMP, 'localtime')".freeze, :CURRENT_TIMESTAMP=>"datetime(CURRENT_TIMESTAMP, 'localtime')".freeze, :CURRENT_TIME=>"time(CURRENT_TIMESTAMP, 'localtime')".freeze}

### Public Instance methods

complex_expression_sql(op, args)

SQLite does not support pattern matching via regular expressions. SQLite is case insensitive (depending on pragma), so use LIKE for ILIKE.

[Source]

         # File lib/sequel/adapters/shared/sqlite.rb, line 320
    320:       def complex_expression_sql(op, args)
    321:         case op
    322:         when :~, '!~''!~', '~*''~*', '!~*''!~*'
    323:           raise Error, "SQLite does not support pattern matching via regular expressions"
    324:         when :LIKE, 'NOT LIKE''NOT LIKE', :ILIKE, 'NOT ILIKE''NOT ILIKE'
    325:           # SQLite is case insensitive for ASCII, and non case sensitive for other character sets
    326:           "#{'NOT ' if [:'NOT LIKE', :'NOT ILIKE'].include?(op)}(#{literal(args.at(0))} LIKE #{literal(args.at(1))})"
    327:         else
    328:           super(op, args)
    329:         end
    330:       end

constant_sql(constant)

MSSQL doesn‘t support the SQL standard CURRENT_DATE or CURRENT_TIME

[Source]

         # File lib/sequel/adapters/shared/sqlite.rb, line 333
    333:       def constant_sql(constant)
    334:         CONSTANT_MAP[constant] || super
    335:       end

delete()

SQLite performs a TRUNCATE style DELETE if no filter is specified. Since we want to always return the count of records, add a condition that is always true and then delete.

[Source]

         # File lib/sequel/adapters/shared/sqlite.rb, line 340
    340:       def delete
    341:         @opts[:where] ? super : filter(1=>1).delete
    342:       end

explain()

Return an array of strings specifying a query explanation for a SELECT of the current dataset.

[Source]

         # File lib/sequel/adapters/shared/sqlite.rb, line 346
    346:       def explain
    347:         db.send(:metadata_dataset).clone(:sql=>"EXPLAIN #{select_sql}").
    348:           map{|x| "#{x[:addr]}|#{x[:opcode]}|#{(1..5).map{|i| x[:"p#{i}"]}.join('|')}|#{x[:comment]}"}
    349:       end

having(*cond, &block)

HAVING requires GROUP BY on SQLite

[Source]

         # File lib/sequel/adapters/shared/sqlite.rb, line 352
    352:       def having(*cond, &block)
    353:         raise(InvalidOperation, "Can only specify a HAVING clause on a grouped dataset") unless @opts[:group]
    354:         super
    355:       end

quoted_identifier(c)

SQLite uses the nonstandard ` (backtick) for quoting identifiers.

[Source]

         # File lib/sequel/adapters/shared/sqlite.rb, line 358
    358:       def quoted_identifier(c)
    359:         "`#{c}`"
    360:       end

supports_intersect_except_all?()

SQLite does not support INTERSECT ALL or EXCEPT ALL

[Source]

         # File lib/sequel/adapters/shared/sqlite.rb, line 363
    363:       def supports_intersect_except_all?
    364:         false
    365:       end

supports_is_true?()

SQLite does not support IS TRUE

[Source]

         # File lib/sequel/adapters/shared/sqlite.rb, line 368
    368:       def supports_is_true?
    369:         false
    370:       end

supports_multiple_column_in?()

SQLite does not support multiple columns for the IN/NOT IN operators

[Source]

         # File lib/sequel/adapters/shared/sqlite.rb, line 373
    373:       def supports_multiple_column_in?
    374:         false
    375:       end

supports_timestamp_timezones?()

SQLite supports timezones in literal timestamps, since it stores them as text.

[Source]

         # File lib/sequel/adapters/shared/sqlite.rb, line 379
    379:       def supports_timestamp_timezones?
    380:         true
    381:       end

[Validate]