Module Sequel::MySQL::DatasetMethods
In: lib/sequel/adapters/shared/mysql.rb

Dataset methods shared by datasets that use MySQL databases.

Methods

Constants

BOOL_TRUE = '1'.freeze
BOOL_FALSE = '0'.freeze
COMMA_SEPARATOR = ', '.freeze
FOR_SHARE = ' LOCK IN SHARE MODE'.freeze
SQL_CALC_FOUND_ROWS = ' SQL_CALC_FOUND_ROWS'.freeze
DELETE_CLAUSE_METHODS = Dataset.clause_methods(:delete, %w'delete from where order limit')
INSERT_CLAUSE_METHODS = Dataset.clause_methods(:insert, %w'insert ignore into columns values on_duplicate_key_update')
SELECT_CLAUSE_METHODS = Dataset.clause_methods(:select, %w'select distinct calc_found_rows columns from join where group having compounds order limit lock')
UPDATE_CLAUSE_METHODS = Dataset.clause_methods(:update, %w'update ignore table set where order limit')
APOS = Dataset::APOS
APOS_RE = Dataset::APOS_RE
DOUBLE_APOS = Dataset::DOUBLE_APOS
SPACE = Dataset::SPACE
PAREN_OPEN = Dataset::PAREN_OPEN
PAREN_CLOSE = Dataset::PAREN_CLOSE
NOT_SPACE = Dataset::NOT_SPACE
FROM = Dataset::FROM
INSERT = Dataset::INSERT
COMMA = Dataset::COMMA
LIMIT = Dataset::LIMIT
GROUP_BY = Dataset::GROUP_BY
REGEXP = 'REGEXP'.freeze
LIKE = 'LIKE'.freeze
BINARY = 'BINARY '.freeze
CONCAT = "CONCAT".freeze
CAST_BITCOMP_OPEN = "CAST(~".freeze
CAST_BITCOMP_CLOSE = " AS SIGNED INTEGER)".freeze
STRAIGHT_JOIN = 'STRAIGHT_JOIN'.freeze
NATURAL_LEFT_JOIN = 'NATURAL LEFT JOIN'.freeze
BACKTICK = '`'.freeze
BACKTICK_RE = /`/.freeze
DOUBLE_BACKTICK = '``'.freeze
EMPTY_COLUMNS = " ()".freeze
EMPTY_VALUES = " VALUES ()".freeze
IGNORE = " IGNORE".freeze
REPLACE = 'REPLACE'.freeze
ON_DUPLICATE_KEY_UPDATE = " ON DUPLICATE KEY UPDATE ".freeze
EQ_VALUES = '=VALUES('.freeze
EQ = '='.freeze
WITH_ROLLUP = ' WITH ROLLUP'.freeze
MATCH_AGAINST = ["(MATCH ".freeze, " AGAINST (".freeze, "))".freeze].freeze
MATCH_AGAINST_BOOLEAN = ["(MATCH ".freeze, " AGAINST (".freeze, " IN BOOLEAN MODE))".freeze].freeze
EXPLAIN = 'EXPLAIN '.freeze
EXPLAIN_EXTENDED = 'EXPLAIN EXTENDED '.freeze
BACKSLASH_RE = /\\/.freeze
QUAD_BACKSLASH = "\\\\\\\\".freeze

Public Instance methods

Sets up the select methods to use SQL_CALC_FOUND_ROWS option.

  dataset.calc_found_rows.limit(10)
  # SELECT SQL_CALC_FOUND_ROWS * FROM table LIMIT 10

[Source]

     # File lib/sequel/adapters/shared/mysql.rb, line 523
523:       def calc_found_rows
524:         clone(:calc_found_rows => true)
525:       end

MySQL specific syntax for LIKE/REGEXP searches, as well as string concatenation.

[Source]

     # File lib/sequel/adapters/shared/mysql.rb, line 479
479:       def complex_expression_sql_append(sql, op, args)
480:         case op
481:         when :IN, "NOT IN""NOT IN"
482:           ds = args.at(1)
483:           if ds.is_a?(Sequel::Dataset) && ds.opts[:limit]
484:             super(sql, op, [args.at(0), ds.from_self])
485:           else
486:             super
487:           end
488:         when :~, '!~''!~', '~*''~*', '!~*''!~*', :LIKE, 'NOT LIKE''NOT LIKE', :ILIKE, 'NOT ILIKE''NOT ILIKE'
489:           sql << PAREN_OPEN
490:           literal_append(sql, args.at(0))
491:           sql << SPACE
492:           sql << 'NOT ' if ['NOT LIKE''NOT LIKE', 'NOT ILIKE''NOT ILIKE', '!~''!~', '!~*''!~*'].include?(op)
493:           sql << ([:~, '!~''!~', '~*''~*', '!~*''!~*'].include?(op) ? REGEXP : LIKE)
494:           sql << SPACE
495:           sql << BINARY if [:~, '!~''!~', :LIKE, 'NOT LIKE''NOT LIKE'].include?(op)
496:           literal_append(sql, args.at(1))
497:           sql << PAREN_CLOSE
498:         when '||''||'
499:           if args.length > 1
500:             sql << CONCAT
501:             array_sql_append(sql, args)
502:           else
503:             literal_append(sql, args.at(0))
504:           end
505:         when 'B~''B~'
506:           sql << CAST_BITCOMP_OPEN
507:           literal_append(sql, args.at(0))
508:           sql << CAST_BITCOMP_CLOSE
509:         else
510:           super
511:         end
512:       end

Use GROUP BY instead of DISTINCT ON if arguments are provided.

[Source]

     # File lib/sequel/adapters/shared/mysql.rb, line 515
515:       def distinct(*args)
516:         args.empty? ? super : group(*args)
517:       end

Return the results of an EXPLAIN query as a string. Options:

:extended :Use EXPLAIN EXPTENDED instead of EXPLAIN if true.

[Source]

     # File lib/sequel/adapters/shared/mysql.rb, line 529
529:       def explain(opts={})
530:         # Load the PrettyTable class, needed for explain output
531:         Sequel.extension(:_pretty_table) unless defined?(Sequel::PrettyTable)
532: 
533:         ds = db.send(:metadata_dataset).with_sql((opts[:extended] ? EXPLAIN_EXTENDED : EXPLAIN) + select_sql).naked
534:         rows = ds.all
535:         Sequel::PrettyTable.string(rows, ds.columns)
536:       end

Return a cloned dataset which will use LOCK IN SHARE MODE to lock returned rows.

[Source]

     # File lib/sequel/adapters/shared/mysql.rb, line 539
539:       def for_share
540:         lock_style(:share)
541:       end

Adds full text filter

[Source]

     # File lib/sequel/adapters/shared/mysql.rb, line 544
544:       def full_text_search(cols, terms, opts = {})
545:         filter(full_text_sql(cols, terms, opts))
546:       end

MySQL specific full text search syntax.

[Source]

     # File lib/sequel/adapters/shared/mysql.rb, line 549
549:       def full_text_sql(cols, terms, opts = {})
550:         terms = terms.join(' ') if terms.is_a?(Array)
551:         SQL::PlaceholderLiteralString.new((opts[:boolean] ? MATCH_AGAINST_BOOLEAN : MATCH_AGAINST), [Array(cols), terms])
552:       end

MySQL allows HAVING clause on ungrouped datasets.

[Source]

     # File lib/sequel/adapters/shared/mysql.rb, line 555
555:       def having(*cond, &block)
556:         _filter(:having, *cond, &block)
557:       end

Sets up the insert methods to use INSERT IGNORE. Useful if you have a unique key and want to just skip inserting rows that violate the unique key restriction.

  dataset.insert_ignore.multi_insert(
   [{:name => 'a', :value => 1}, {:name => 'b', :value => 2}]
  )
  # INSERT IGNORE INTO tablename (name, value) VALUES (a, 1), (b, 2)

[Source]

     # File lib/sequel/adapters/shared/mysql.rb, line 588
588:       def insert_ignore
589:         clone(:insert_ignore=>true)
590:       end

Transforms an CROSS JOIN to an INNER JOIN if the expr is not nil. Raises an error on use of :full_outer type, since MySQL doesn‘t support it.

[Source]

     # File lib/sequel/adapters/shared/mysql.rb, line 561
561:       def join_table(type, table, expr=nil, table_alias={}, &block)
562:         type = :inner if (type == :cross) && !expr.nil?
563:         raise(Sequel::Error, "MySQL doesn't support FULL OUTER JOIN") if type == :full_outer
564:         super(type, table, expr, table_alias, &block)
565:       end

Transforms :natural_inner to NATURAL LEFT JOIN and straight to STRAIGHT_JOIN.

[Source]

     # File lib/sequel/adapters/shared/mysql.rb, line 569
569:       def join_type_sql(join_type)
570:         case join_type
571:         when :straight
572:           STRAIGHT_JOIN
573:         when :natural_inner
574:           NATURAL_LEFT_JOIN
575:         else
576:           super
577:         end
578:       end

MySQL specific syntax for inserting multiple values at once.

[Source]

     # File lib/sequel/adapters/shared/mysql.rb, line 616
616:       def multi_insert_sql(columns, values)
617:         sql = LiteralString.new('VALUES ')
618:         expression_list_append(sql, values.map{|r| Array(r)})
619:         [insert_sql(columns, sql)]
620:       end

Replace multiple rows in a single query.

[Source]

     # File lib/sequel/adapters/shared/mysql.rb, line 639
639:       def multi_replace(*values)
640:         clone(:replace=>true).multi_insert(*values)
641:       end

Sets up the insert methods to use ON DUPLICATE KEY UPDATE If you pass no arguments, ALL fields will be updated with the new values. If you pass the fields you want then ONLY those field will be updated.

Useful if you have a unique key and want to update inserting rows that violate the unique key restriction.

  dataset.on_duplicate_key_update.multi_insert(
   [{:name => 'a', :value => 1}, {:name => 'b', :value => 2}]
  )
  # INSERT INTO tablename (name, value) VALUES (a, 1), (b, 2)
  # ON DUPLICATE KEY UPDATE name=VALUES(name), value=VALUES(value)

  dataset.on_duplicate_key_update(:value).multi_insert(
    [{:name => 'a', :value => 1}, {:name => 'b', :value => 2}]
  )
  # INSERT INTO tablename (name, value) VALUES (a, 1), (b, 2)
  # ON DUPLICATE KEY UPDATE value=VALUES(value)

[Source]

     # File lib/sequel/adapters/shared/mysql.rb, line 611
611:       def on_duplicate_key_update(*args)
612:         clone(:on_duplicate_key_update => args)
613:       end

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

[Source]

     # File lib/sequel/adapters/shared/mysql.rb, line 623
623:       def quoted_identifier_append(sql, c)
624:         sql << BACKTICK << c.to_s.gsub(BACKTICK_RE, DOUBLE_BACKTICK) << BACKTICK
625:       end

Execute a REPLACE statement on the database.

[Source]

     # File lib/sequel/adapters/shared/mysql.rb, line 628
628:       def replace(*values)
629:         execute_insert(replace_sql(*values))
630:       end

MySQL specific syntax for REPLACE (aka UPSERT, or update if exists, insert if it doesn‘t).

[Source]

     # File lib/sequel/adapters/shared/mysql.rb, line 634
634:       def replace_sql(*values)
635:         clone(:replace=>true).insert_sql(*values)
636:       end

MySQL can emulate DISTINCT ON with its non-standard GROUP BY implementation, though the rows returned cannot be made deterministic through ordering.

[Source]

     # File lib/sequel/adapters/shared/mysql.rb, line 645
645:       def supports_distinct_on?
646:         true
647:       end

MySQL supports GROUP BY WITH ROLLUP (but not CUBE)

[Source]

     # File lib/sequel/adapters/shared/mysql.rb, line 650
650:       def supports_group_rollup?
651:         true
652:       end

MySQL does not support INTERSECT or EXCEPT

[Source]

     # File lib/sequel/adapters/shared/mysql.rb, line 655
655:       def supports_intersect_except?
656:         false
657:       end

MySQL supports modifying joined datasets

[Source]

     # File lib/sequel/adapters/shared/mysql.rb, line 660
660:       def supports_modifying_joins?
661:         true
662:       end

MySQL‘s DISTINCT ON emulation using GROUP BY does not respect the queries ORDER BY clause.

[Source]

     # File lib/sequel/adapters/shared/mysql.rb, line 666
666:       def supports_ordered_distinct_on?
667:         false
668:       end

MySQL does support fractional timestamps in literal timestamps, but it ignores them. Also, using them seems to cause problems on 1.9. Since they are ignored anyway, not using them is probably best.

[Source]

     # File lib/sequel/adapters/shared/mysql.rb, line 673
673:       def supports_timestamp_usecs?
674:         false
675:       end

Sets up the update methods to use UPDATE IGNORE. Useful if you have a unique key and want to just skip updating rows that violate the unique key restriction.

  dataset.update_ignore.update({:name => 'a', :value => 1})
  # UPDATE IGNORE tablename SET name = 'a', value = 1

[Source]

     # File lib/sequel/adapters/shared/mysql.rb, line 683
683:       def update_ignore
684:         clone(:update_ignore=>true)
685:       end

[Validate]