Module: Sequel::MySQL::DatasetMethods

Includes:
Dataset::Replace, UnmodifiedIdentifiers::DatasetMethods
Included in:
Dataset, Sequel::Mysql2::Dataset
Defined in:
lib/sequel/adapters/shared/mysql.rb

Overview

Dataset methods shared by datasets that use MySQL databases.

Constant Summary collapse

MATCH_AGAINST = 
["MATCH ".freeze, " AGAINST (".freeze, ")".freeze].freeze
MATCH_AGAINST_BOOLEAN = 
["MATCH ".freeze, " AGAINST (".freeze, " IN BOOLEAN MODE)".freeze].freeze

Instance Method Summary collapse

Methods included from Dataset::Replace

#multi_replace, #replace, #replace_sql, #supports_replace?

Instance Method Details

#calc_found_rows ⇒ Object

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



614
615
616
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 614

def calc_found_rows
  clone(:calc_found_rows => true)
end

#complex_expression_sql_append(sql, op, args) ⇒ Object 


554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 554

def complex_expression_sql_append(sql, op, args)
  case op
  when :IN, :"NOT IN"
    ds = args[1]
    if ds.is_a?(Sequel::Dataset) && ds.opts[:limit]
      super(sql, op, [args[0], ds.from_self])
    else
      super
    end
  when :~, :'!~', :'~*', :'!~*', :LIKE, :'NOT LIKE', :ILIKE, :'NOT ILIKE'
    sql << '('
    literal_append(sql, args[0])
    sql << ' '
    sql << 'NOT ' if [:'NOT LIKE', :'NOT ILIKE', :'!~', :'!~*'].include?(op)
    sql << ([:~, :'!~', :'~*', :'!~*'].include?(op) ? 'REGEXP' : 'LIKE')
    sql << ' '
    sql << 'BINARY ' if [:~, :'!~', :LIKE, :'NOT LIKE'].include?(op)
    literal_append(sql, args[1])
    if [:LIKE, :'NOT LIKE', :ILIKE, :'NOT ILIKE'].include?(op)
      sql << " ESCAPE "
      literal_append(sql, "\\")
    end
    sql << ')'
  when :'||'
    if args.length > 1
      sql << "CONCAT"
      array_sql_append(sql, args)
    else
      literal_append(sql, args[0])
    end
  when :'B~'
    sql << "CAST(~"
    literal_append(sql, args[0])
    sql << " AS SIGNED INTEGER)"
  else
    super
  end
end

#constant_sql_append(sql, constant) ⇒ Object

MySQL's CURRENT_TIMESTAMP does not use fractional seconds, even if the database itself supports fractional seconds. If MySQL 5.6.4+ is being used, use a value that will return fractional seconds.


597
598
599
600
601
602
603
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 597

def constant_sql_append(sql, constant)
  if constant == :CURRENT_TIMESTAMP && supports_timestamp_usecs?
    sql << 'CURRENT_TIMESTAMP(6)'
  else
    super
  end
end

#delete_from(*tables) ⇒ Object

Sets up the select methods to delete from if deleting from a joined dataset:

DB[:a].join(:b, a_id: :id).delete# DELETE a FROM a INNER JOIN b ON (b.a_id = a.id)


DB[:a].join(:b, a_id: :id).delete_from(:a, :b).delete# DELETE a, b FROM a INNER JOIN b ON (b.a_id = a.id)



626
627
628
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 626

def delete_from(*tables)
  clone(:delete_from=>tables)
end

#distinct(*args) ⇒ Object

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


606
607
608
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 606

def distinct(*args)
  args.empty? ? super : group(*args)
end

#explain(opts = OPTS) ⇒ Object

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

:extended

Use EXPLAIN EXPTENDED instead of EXPLAIN if true.


632
633
634
635
636
637
638
639
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 632

def explain(opts=OPTS)
  # Load the PrettyTable class, needed for explain output
  Sequel.extension(:_pretty_table) unless defined?(Sequel::PrettyTable)

  ds = db.send(:metadata_dataset).with_sql((opts[:extended] ? 'EXPLAIN EXTENDED ' : 'EXPLAIN ') + select_sql).naked
  rows = ds.all
  Sequel::PrettyTable.string(rows, ds.columns)
end

#for_share ⇒ Object

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


642
643
644
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 642

def for_share
  lock_style(:share)
end

#full_text_search(cols, terms, opts = OPTS) ⇒ Object

Adds full text filter


647
648
649
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 647

def full_text_search(cols, terms, opts = OPTS)
  where(full_text_sql(cols, terms, opts))
end

#full_text_sql(cols, terms, opts = OPTS) ⇒ Object

MySQL specific full text search syntax.


652
653
654
655
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 652

def full_text_sql(cols, terms, opts = OPTS)
  terms = terms.join(' ') if terms.is_a?(Array)
  SQL::PlaceholderLiteralString.new((opts[:boolean] ? MATCH_AGAINST_BOOLEAN : MATCH_AGAINST), [Array(cols), terms])
end

#insert_ignore ⇒ Object

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)



674
675
676
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 674

def insert_ignore
  clone(:insert_ignore=>true)
end

#join_type_sql(join_type) ⇒ Object

Transforms :straight to STRAIGHT_JOIN.


658
659
660
661
662
663
664
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 658

def join_type_sql(join_type)
  if join_type == :straight
    'STRAIGHT_JOIN'
  else
    super
  end
end

#on_duplicate_key_update(*args) ⇒ Object

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. If you pass a hash you can customize the values (for example, to increment a numeric field).

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)


dataset.on_duplicate_key_update(
  value: Sequel.lit('value + VALUES(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=value + VALUES(value)



707
708
709
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 707

def on_duplicate_key_update(*args)
  clone(:on_duplicate_key_update => args)
end

#quoted_identifier_append(sql, c) ⇒ Object

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


712
713
714
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 712

def quoted_identifier_append(sql, c)
  sql << '`' << c.to_s.gsub('`', '``') << '`'
end

#supports_derived_column_lists? ⇒ Boolean

MySQL does not support derived column lists


717
718
719
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 717

def supports_derived_column_lists?
  false
end

#supports_distinct_on? ⇒ Boolean

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


723
724
725
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 723

def supports_distinct_on?
  true
end

#supports_group_rollup? ⇒ Boolean

MySQL supports GROUP BY WITH ROLLUP (but not CUBE)


728
729
730
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 728

def supports_group_rollup?
  true
end

#supports_intersect_except? ⇒ Boolean

MySQL does not support INTERSECT or EXCEPT


733
734
735
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 733

def supports_intersect_except?
  false
end

#supports_limits_in_correlated_subqueries? ⇒ Boolean

MySQL does not support limits in correlated subqueries (or any subqueries that use IN).


738
739
740
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 738

def supports_limits_in_correlated_subqueries?
  false
end

#supports_modifying_joins? ⇒ Boolean

MySQL supports modifying joined datasets


743
744
745
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 743

def supports_modifying_joins?
  true
end

#supports_ordered_distinct_on? ⇒ Boolean

MySQL's DISTINCT ON emulation using GROUP BY does not respect the query's ORDER BY clause.


749
750
751
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 749

def supports_ordered_distinct_on?
  false
end

#supports_regexp? ⇒ Boolean

MySQL supports pattern matching via regular expressions


754
755
756
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 754

def supports_regexp?
  true
end

#supports_timestamp_usecs? ⇒ Boolean

Check the database setting for whether fractional timestamps are suppported.


760
761
762
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 760

def supports_timestamp_usecs?
  db.supports_timestamp_usecs?
end

#update_ignore ⇒ Object

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



770
771
772
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 770

def update_ignore
  clone(:update_ignore=>true)
end