Module: Sequel::SQLite::DatasetMethods

Constants

 Dataset.clause_methods(:select, %w'select distinct columns from join where group having compounds order limit')
 {:CURRENT_DATE=>"date(CURRENT_TIMESTAMP, 'localtime')".freeze, :CURRENT_TIMESTAMP=>"datetime(CURRENT_TIMESTAMP, 'localtime')".freeze, :CURRENT_TIME=>"time(CURRENT_TIMESTAMP, 'localtime')".freeze}
 {:year=>"'%Y'", :month=>"'%m'", :day=>"'%d'", :hour=>"'%H'", :minute=>"'%M'", :second=>"'%f'"}
 Dataset::NOT_SPACE
 Dataset::COMMA
 Dataset::PAREN_CLOSE
 Dataset::AS
 Dataset::APOS
 "CAST(strftime(".freeze
 ') AS '.freeze
 'NUMERIC'.freeze
 'INTEGER'.freeze
 '`'.freeze
 "X'".freeze
 "H*".freeze

Public Instance methods

complex_expression_sql_append(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 418
418:       def complex_expression_sql_append(sql, op, args)
419:         case op
420:         when :~, '!~''!~', '~*''~*', '!~*''!~*'
421:           raise Error, "SQLite does not support pattern matching via regular expressions"
422:         when :ILIKE
423:           super(sql, :LIKE, args.map{|a| SQL::Function.new(:upper, a)})
424:         when "NOT LIKE""NOT LIKE", "NOT ILIKE""NOT ILIKE"
425:           sql << NOT_SPACE
426:           complex_expression_sql_append(sql, (op == "NOT ILIKE""NOT ILIKE" ? :ILIKE : :LIKE), args)
427:         when :^
428:           sql << complex_expression_arg_pairs(args) do |a, b|
429:             a = literal(a)
430:             b = literal(b)
431:             "((~(#{a} & #{b})) & (#{a} | #{b}))"
432:           end
433:         when :extract
434:           part = args.at(0)
435:           raise(Sequel::Error, "unsupported extract argument: #{part.inspect}") unless format = EXTRACT_MAP[part]
436:           sql << EXTRACT_OPEN << format << COMMA
437:           literal_append(sql, args.at(1))
438:           sql << EXTRACT_CLOSE << (part == :second ? NUMERIC : INTEGER) << PAREN_CLOSE
439:         else
440:           super
441:         end
442:       end

constant_sql_append(sql, constant)

SQLite has CURRENT_TIMESTAMP and related constants in UTC instead of in localtime, so convert those constants to local time.

[Source]

     # File lib/sequel/adapters/shared/sqlite.rb, line 446
446:       def constant_sql_append(sql, constant)
447:         if c = CONSTANT_MAP[constant]
448:           sql << c
449:         else
450:           super
451:         end
452:       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 457
457:       def delete
458:         @opts[:where] ? super : filter(1=>1).delete
459:       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 463
463:       def explain
464:         db.send(:metadata_dataset).clone(:sql=>"EXPLAIN #{select_sql}").
465:           map{|x| "#{x[:addr]}|#{x[:opcode]}|#{(1..5).map{|i| x[:"p#{i}"]}.join('|')}|#{x[:comment]}"}
466:       end

having(*cond)

HAVING requires GROUP BY on SQLite

[Source]

     # File lib/sequel/adapters/shared/sqlite.rb, line 469
469:       def having(*cond)
470:         raise(InvalidOperation, "Can only specify a HAVING clause on a grouped dataset") unless @opts[:group]
471:         super
472:       end

quoted_identifier_append(sql, c)

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

[Source]

     # File lib/sequel/adapters/shared/sqlite.rb, line 475
475:       def quoted_identifier_append(sql, c)
476:         sql << BACKTICK << c.to_s << BACKTICK
477:       end

select(*cols)

When a qualified column is selected on SQLite and the qualifier is a subselect, the column name used is the full qualified name (including the qualifier) instead of just the column name. To get correct column names, you must use an alias.

[Source]

     # File lib/sequel/adapters/shared/sqlite.rb, line 483
483:       def select(*cols)
484:         if ((f = @opts[:from]) && f.any?{|t| t.is_a?(Dataset) || (t.is_a?(SQL::AliasedExpression) && t.expression.is_a?(Dataset))}) || ((j = @opts[:join]) && j.any?{|t| t.table.is_a?(Dataset)})
485:           super(*cols.map{|c| alias_qualified_column(c)})
486:         else
487:           super
488:         end
489:       end

supports_intersect_except_all?()

SQLite does not support INTERSECT ALL or EXCEPT ALL

[Source]

     # File lib/sequel/adapters/shared/sqlite.rb, line 492
492:       def supports_intersect_except_all?
493:         false
494:       end

supports_is_true?()

SQLite does not support IS TRUE

[Source]

     # File lib/sequel/adapters/shared/sqlite.rb, line 497
497:       def supports_is_true?
498:         false
499:       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 502
502:       def supports_multiple_column_in?
503:         false
504:       end

supports_timestamp_timezones?()

SQLite supports timezones in literal timestamps, since it stores them as text. But using timezones in timestamps breaks SQLite datetime functions, so we allow the user to override the default per database.

[Source]

     # File lib/sequel/adapters/shared/sqlite.rb, line 509
509:       def supports_timestamp_timezones?
510:         db.use_timestamp_timezones?
511:       end

supports_where_true?()

SQLite cannot use WHERE ‘t’.

[Source]

     # File lib/sequel/adapters/shared/sqlite.rb, line 514
514:       def supports_where_true?
515:         false
516:       end