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



666
667
668
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 666

def calc_found_rows
  clone(:calc_found_rows => true)
end

#complex_expression_sql_append(sql, op, args) ⇒ Object 



600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 600

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'
    if !db.mariadb? && db.server_version >= 80000 && [:~, :'!~'].include?(op)
      func = Sequel.function(:REGEXP_LIKE, args[0], args[1], 'c')
      func = ~func if op == :'!~'
      return literal_append(sql, func)
    end

    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.



649
650
651
652
653
654
655
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 649

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)



678
679
680
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 678

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

#distinct(*args) ⇒ Object

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



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

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.



684
685
686
687
688
689
690
691
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 684

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] && (db.mariadb? || db.server_version < 50700)) ? '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.



694
695
696
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 694

def for_share
  lock_style(:share)
end

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

Adds full text filter



699
700
701
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 699

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.



704
705
706
707
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 704

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)



726
727
728
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 726

def insert_ignore
  clone(:insert_ignore=>true)
end

#join_type_sql(join_type) ⇒ Object

Transforms :straight to STRAIGHT_JOIN.



710
711
712
713
714
715
716
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 710

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)



759
760
761
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 759

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.



764
765
766
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 764

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

#supports_cte?(type = :select) ⇒ Boolean

MariaDB 10.2+ and MySQL 8+ support CTEs

Returns:

  • (Boolean) 


769
770
771
772
773
774
775
776
777
778
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 769

def supports_cte?(type=:select)
  if db.mariadb?
    type == :select && db.server_version >= 100200
  else
    case type
    when :select, :update, :delete
      db.server_version >= 80000
    end
  end
end

#supports_derived_column_lists? ⇒ Boolean

MySQL does not support derived column lists

Returns:

  • (Boolean) 


781
782
783
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 781

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.

Returns:

  • (Boolean) 


787
788
789
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 787

def supports_distinct_on?
  true
end

#supports_group_rollup? ⇒ Boolean

MySQL supports GROUP BY WITH ROLLUP (but not CUBE)

Returns:

  • (Boolean) 


792
793
794
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 792

def supports_group_rollup?
  true
end

#supports_intersect_except? ⇒ Boolean

MySQL does not support INTERSECT or EXCEPT

Returns:

  • (Boolean) 


797
798
799
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 797

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).

Returns:

  • (Boolean) 


802
803
804
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 802

def supports_limits_in_correlated_subqueries?
  false
end

#supports_modifying_joins? ⇒ Boolean

MySQL supports modifying joined datasets

Returns:

  • (Boolean) 


807
808
809
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 807

def supports_modifying_joins?
  true
end

#supports_nowait? ⇒ Boolean

MySQL 8+ supports NOWAIT.

Returns:

  • (Boolean) 


812
813
814
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 812

def supports_nowait?
  !db.mariadb? && db.server_version >= 80000
end

#supports_ordered_distinct_on? ⇒ Boolean

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

Returns:

  • (Boolean) 


818
819
820
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 818

def supports_ordered_distinct_on?
  false
end

#supports_regexp? ⇒ Boolean

MySQL supports pattern matching via regular expressions

Returns:

  • (Boolean) 


823
824
825
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 823

def supports_regexp?
  true
end

#supports_skip_locked? ⇒ Boolean

MySQL 8+ supports SKIP LOCKED.

Returns:

  • (Boolean) 


828
829
830
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 828

def supports_skip_locked?
  !db.mariadb? && db.server_version >= 80000
end

#supports_timestamp_usecs? ⇒ Boolean

Check the database setting for whether fractional timestamps are suppported.

Returns:

  • (Boolean) 


834
835
836
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 834

def supports_timestamp_usecs?
  db.supports_timestamp_usecs?
end

#supports_window_functions? ⇒ Boolean

MariaDB 10.2+ and MySQL 8+ support window functions

Returns:

  • (Boolean) 


839
840
841
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 839

def supports_window_functions?
  db.server_version >= (db.mariadb? ? 100200 : 80000)
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



849
850
851
 
# File 'lib/sequel/adapters/shared/mysql.rb', line 849

def update_ignore
  clone(:update_ignore=>true)
end