module Sequel::MySQL::DatasetMethods

Dataset methods shared by datasets that use MySQL databases.

Constants

MATCH_AGAINST
MATCH_AGAINST_BOOLEAN

Public Instance Methods

calc_found_rows() click to toggle source

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
    # File lib/sequel/adapters/shared/mysql.rb
722 def calc_found_rows
723   clone(:calc_found_rows => true)
724 end
complex_expression_sql_append(sql, op, args) click to toggle source
Calls superclass method
    # File lib/sequel/adapters/shared/mysql.rb
656 def complex_expression_sql_append(sql, op, args)
657   case op
658   when :IN, :"NOT IN"
659     ds = args[1]
660     if ds.is_a?(Sequel::Dataset) && ds.opts[:limit]
661       super(sql, op, [args[0], ds.from_self])
662     else
663       super
664     end
665   when :~, :'!~', :'~*', :'!~*', :LIKE, :'NOT LIKE', :ILIKE, :'NOT ILIKE'
666     if !db.mariadb? && db.server_version >= 80000 && [:~, :'!~'].include?(op)
667       func = Sequel.function(:REGEXP_LIKE, args[0], args[1], 'c')
668       func = ~func if op == :'!~'
669       return literal_append(sql, func)
670     end
671 
672     sql << '('
673     literal_append(sql, args[0])
674     sql << ' '
675     sql << 'NOT ' if [:'NOT LIKE', :'NOT ILIKE', :'!~', :'!~*'].include?(op)
676     sql << ([:~, :'!~', :'~*', :'!~*'].include?(op) ? 'REGEXP' : 'LIKE')
677     sql << ' '
678     sql << 'BINARY ' if [:~, :'!~', :LIKE, :'NOT LIKE'].include?(op)
679     literal_append(sql, args[1])
680     if [:LIKE, :'NOT LIKE', :ILIKE, :'NOT ILIKE'].include?(op)
681       sql << " ESCAPE "
682       literal_append(sql, "\\")
683     end
684     sql << ')'
685   when :'||'
686     if args.length > 1
687       sql << "CONCAT"
688       array_sql_append(sql, args)
689     else
690       literal_append(sql, args[0])
691     end
692   when :'B~'
693     sql << "CAST(~"
694     literal_append(sql, args[0])
695     sql << " AS SIGNED INTEGER)"
696   else
697     super
698   end
699 end
constant_sql_append(sql, constant) click to toggle source

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.

Calls superclass method
    # File lib/sequel/adapters/shared/mysql.rb
705 def constant_sql_append(sql, constant)
706   if constant == :CURRENT_TIMESTAMP && supports_timestamp_usecs?
707     sql << 'CURRENT_TIMESTAMP(6)'
708   else
709     super
710   end
711 end
delete_from(*tables) click to toggle source

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)
    # File lib/sequel/adapters/shared/mysql.rb
734 def delete_from(*tables)
735   clone(:delete_from=>tables)
736 end
distinct(*args) click to toggle source

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

Calls superclass method
    # File lib/sequel/adapters/shared/mysql.rb
714 def distinct(*args)
715   args.empty? ? super : group(*args)
716 end
explain(opts=OPTS) click to toggle source

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

:extended

Use EXPLAIN EXTENDED instead of EXPLAIN if true.

    # File lib/sequel/adapters/shared/mysql.rb
740 def explain(opts=OPTS)
741   # Load the PrettyTable class, needed for explain output
742   Sequel.extension(:_pretty_table) unless defined?(Sequel::PrettyTable)
743 
744   ds = db.send(:metadata_dataset).with_sql(((opts[:extended] && (db.mariadb? || db.server_version < 50700)) ? 'EXPLAIN EXTENDED ' : 'EXPLAIN ') + select_sql).naked
745   rows = ds.all
746   Sequel::PrettyTable.string(rows, ds.columns)
747 end
for_share() click to toggle source

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

    # File lib/sequel/adapters/shared/mysql.rb
750 def for_share
751   lock_style(:share)
752 end
full_text_sql(cols, terms, opts = OPTS) click to toggle source

MySQL specific full text search syntax.

    # File lib/sequel/adapters/shared/mysql.rb
760 def full_text_sql(cols, terms, opts = OPTS)
761   terms = terms.join(' ') if terms.is_a?(Array)
762   SQL::PlaceholderLiteralString.new((opts[:boolean] ? MATCH_AGAINST_BOOLEAN : MATCH_AGAINST), [Array(cols), terms])
763 end
insert_ignore() click to toggle source

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)
    # File lib/sequel/adapters/shared/mysql.rb
773 def insert_ignore
774   clone(:insert_ignore=>true)
775 end
on_duplicate_key_update(*args) click to toggle source

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)
    # File lib/sequel/adapters/shared/mysql.rb
806 def on_duplicate_key_update(*args)
807   clone(:on_duplicate_key_update => args)
808 end
quoted_identifier_append(sql, c) click to toggle source

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

    # File lib/sequel/adapters/shared/mysql.rb
811 def quoted_identifier_append(sql, c)
812   sql << '`' << c.to_s.gsub('`', '``') << '`'
813 end
supports_cte?(type=:select) click to toggle source

MariaDB 10.2+ and MySQL 8+ support CTEs

    # File lib/sequel/adapters/shared/mysql.rb
816 def supports_cte?(type=:select)
817   if db.mariadb?
818     type == :select && db.server_version >= 100200
819   else
820     case type
821     when :select, :update, :delete
822       db.server_version >= 80000
823     end
824   end
825 end
supports_derived_column_lists?() click to toggle source

MySQL does not support derived column lists

    # File lib/sequel/adapters/shared/mysql.rb
828 def supports_derived_column_lists?
829   false
830 end
supports_distinct_on?() click to toggle source

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

    # File lib/sequel/adapters/shared/mysql.rb
834 def supports_distinct_on?
835   true
836 end
supports_group_rollup?() click to toggle source

MySQL supports GROUP BY WITH ROLLUP (but not CUBE)

    # File lib/sequel/adapters/shared/mysql.rb
839 def supports_group_rollup?
840   true
841 end
supports_intersect_except?() click to toggle source

MariaDB 10.3+ supports INTERSECT or EXCEPT

    # File lib/sequel/adapters/shared/mysql.rb
844 def supports_intersect_except?
845   db.mariadb? && db.server_version >= 100300
846 end
supports_limits_in_correlated_subqueries?() click to toggle source

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

    # File lib/sequel/adapters/shared/mysql.rb
849 def supports_limits_in_correlated_subqueries?
850   false
851 end
supports_modifying_joins?() click to toggle source

MySQL supports modifying joined datasets

    # File lib/sequel/adapters/shared/mysql.rb
854 def supports_modifying_joins?
855   true
856 end
supports_nowait?() click to toggle source

MySQL 8+ and MariaDB 10.3+ support NOWAIT.

    # File lib/sequel/adapters/shared/mysql.rb
859 def supports_nowait?
860   db.server_version >= (db.mariadb? ? 100300 : 80000)
861 end
supports_ordered_distinct_on?() click to toggle source

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

    # File lib/sequel/adapters/shared/mysql.rb
865 def supports_ordered_distinct_on?
866   false
867 end
supports_regexp?() click to toggle source

MySQL supports pattern matching via regular expressions

    # File lib/sequel/adapters/shared/mysql.rb
870 def supports_regexp?
871   true
872 end
supports_skip_locked?() click to toggle source

MySQL 8+ supports SKIP LOCKED.

    # File lib/sequel/adapters/shared/mysql.rb
875 def supports_skip_locked?
876   !db.mariadb? && db.server_version >= 80000
877 end
supports_timestamp_usecs?() click to toggle source

Check the database setting for whether fractional timestamps are suppported.

    # File lib/sequel/adapters/shared/mysql.rb
881 def supports_timestamp_usecs?
882   db.supports_timestamp_usecs?
883 end
supports_window_clause?() click to toggle source

MySQL 8+ supports WINDOW clause.

    # File lib/sequel/adapters/shared/mysql.rb
886 def supports_window_clause?
887   !db.mariadb? && db.server_version >= 80000
888 end
supports_window_functions?() click to toggle source

MariaDB 10.2+ and MySQL 8+ support window functions

    # File lib/sequel/adapters/shared/mysql.rb
891 def supports_window_functions?
892   db.server_version >= (db.mariadb? ? 100200 : 80000)
893 end
update_ignore() click to toggle source

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
    # File lib/sequel/adapters/shared/mysql.rb
901 def update_ignore
902   clone(:update_ignore=>true)
903 end

Private Instance Methods

check_not_limited!(type) click to toggle source

Allow update and delete for limited datasets, unless there is an offset.

Calls superclass method
    # File lib/sequel/adapters/shared/mysql.rb
908 def check_not_limited!(type)
909   super if type == :truncate || @opts[:offset]
910 end
delete_from_sql(sql) click to toggle source

Consider the first table in the joined dataset is the table to delete from, but include the others for the purposes of selecting rows.

Calls superclass method
    # File lib/sequel/adapters/shared/mysql.rb
914 def delete_from_sql(sql)
915   if joined_dataset?
916     sql << ' '
917     tables = @opts[:delete_from] || @opts[:from][0..0]
918     source_list_append(sql, tables)
919     sql << ' FROM '
920     source_list_append(sql, @opts[:from])
921     select_join_sql(sql)
922   else
923     super
924   end
925 end
delete_limit_sql(sql)
Alias for: limit_sql
insert_columns_sql(sql) click to toggle source

MySQL doesn't use the SQL standard DEFAULT VALUES.

Calls superclass method
    # File lib/sequel/adapters/shared/mysql.rb
928 def insert_columns_sql(sql)
929   values = opts[:values]
930   if values.is_a?(Array) && values.empty?
931     sql << " ()"
932   else
933     super
934   end
935 end
insert_ignore_sql(sql) click to toggle source

MySQL supports INSERT IGNORE INTO

    # File lib/sequel/adapters/shared/mysql.rb
938 def insert_ignore_sql(sql)
939   sql << " IGNORE" if opts[:insert_ignore]
940 end
insert_on_duplicate_key_update_sql(sql) click to toggle source

MySQL supports INSERT … ON DUPLICATE KEY UPDATE

    # File lib/sequel/adapters/shared/mysql.rb
948 def insert_on_duplicate_key_update_sql(sql)
949   if update_cols = opts[:on_duplicate_key_update]
950     update_vals = nil
951 
952     if update_cols.empty?
953       update_cols = columns
954     elsif update_cols.last.is_a?(Hash)
955       update_vals = update_cols.last
956       update_cols = update_cols[0..-2]
957     end
958 
959     sql << " ON DUPLICATE KEY UPDATE "
960     c = false
961     co = ', '
962     values = '=VALUES('
963     endp = ')'
964     update_cols.each do |col|
965       sql << co if c
966       quote_identifier_append(sql, col)
967       sql << values
968       quote_identifier_append(sql, col)
969       sql << endp
970       c ||= true
971     end
972     if update_vals
973       eq = '='
974       update_vals.map do |col,v| 
975         sql << co if c
976         quote_identifier_append(sql, col)
977         sql << eq
978         literal_append(sql, v)
979         c ||= true
980       end
981     end
982   end
983 end
insert_values_sql(sql) click to toggle source

MySQL doesn't use the standard DEFAULT VALUES for empty values.

Calls superclass method
    # File lib/sequel/adapters/shared/mysql.rb
986 def insert_values_sql(sql)
987   values = opts[:values]
988   if values.is_a?(Array) && values.empty?
989     sql << " VALUES ()"
990   else
991     super
992   end
993 end
join_type_sql(join_type) click to toggle source

Transforms :straight to STRAIGHT_JOIN.

Calls superclass method
     # File lib/sequel/adapters/shared/mysql.rb
 996 def join_type_sql(join_type)
 997   if join_type == :straight
 998     'STRAIGHT_JOIN'
 999   else
1000     super
1001   end
1002 end
limit_sql(sql) click to toggle source

MySQL allows a LIMIT in DELETE and UPDATE statements.

     # File lib/sequel/adapters/shared/mysql.rb
1005 def limit_sql(sql)
1006   if l = @opts[:limit]
1007     sql << " LIMIT "
1008     literal_append(sql, l)
1009   end
1010 end
literal_blob_append(sql, v) click to toggle source

MySQL uses a preceding X for hex escaping strings

     # File lib/sequel/adapters/shared/mysql.rb
1015 def literal_blob_append(sql, v)
1016   if v.empty?
1017     sql << "''"
1018   else
1019     sql << "0x" << v.unpack("H*").first
1020   end
1021 end
literal_false() click to toggle source

Use 0 for false on MySQL

     # File lib/sequel/adapters/shared/mysql.rb
1024 def literal_false
1025   '0'
1026 end
literal_float(v) click to toggle source

Raise error for infinitate and NaN values

Calls superclass method
     # File lib/sequel/adapters/shared/mysql.rb
1029 def literal_float(v)
1030   if v.infinite? || v.nan?
1031     raise InvalidValue, "Infinite floats and NaN values are not valid on MySQL"
1032   else
1033     super
1034   end
1035 end
literal_string_append(sql, v) click to toggle source

SQL fragment for String. Doubles \ and ' by default.

     # File lib/sequel/adapters/shared/mysql.rb
1038 def literal_string_append(sql, v)
1039   sql << "'" << v.gsub("\\", "\\\\\\\\").gsub("'", "''") << "'"
1040 end
literal_true() click to toggle source

Use 1 for true on MySQL

     # File lib/sequel/adapters/shared/mysql.rb
1043 def literal_true
1044   '1'
1045 end
multi_insert_sql_strategy() click to toggle source

MySQL supports multiple rows in VALUES in INSERT.

     # File lib/sequel/adapters/shared/mysql.rb
1048 def multi_insert_sql_strategy
1049   :values
1050 end
non_sql_option?(key) click to toggle source
Calls superclass method
     # File lib/sequel/adapters/shared/mysql.rb
1052 def non_sql_option?(key)
1053   super || key == :insert_ignore || key == :update_ignore || key == :on_duplicate_key_update
1054 end
requires_emulating_nulls_first?() click to toggle source

MySQL does not natively support NULLS FIRST/LAST.

     # File lib/sequel/adapters/shared/mysql.rb
1057 def requires_emulating_nulls_first?
1058   true
1059 end
select_calc_found_rows_sql(sql) click to toggle source

MySQL specific SQL_CALC_FOUND_ROWS option

     # File lib/sequel/adapters/shared/mysql.rb
1091 def select_calc_found_rows_sql(sql)
1092   sql << ' SQL_CALC_FOUND_ROWS' if opts[:calc_found_rows]
1093 end
select_lock_sql(sql) click to toggle source

Support FOR SHARE locking when using the :share lock style. Use SKIP LOCKED if skipping locked rows.

Calls superclass method
     # File lib/sequel/adapters/shared/mysql.rb
1069 def select_lock_sql(sql)
1070   lock = @opts[:lock]
1071   if lock == :share
1072     if !db.mariadb? && db.server_version >= 80000
1073       sql << ' FOR SHARE'
1074     else
1075       sql << ' LOCK IN SHARE MODE'
1076     end
1077   else
1078     super
1079   end
1080 
1081   if lock
1082     if @opts[:skip_locked]
1083       sql << " SKIP LOCKED"
1084     elsif @opts[:nowait]
1085       sql << " NOWAIT"
1086     end
1087   end
1088 end
select_only_offset_sql(sql) click to toggle source
     # File lib/sequel/adapters/shared/mysql.rb
1061 def select_only_offset_sql(sql)
1062   sql << " LIMIT "
1063   literal_append(sql, @opts[:offset])
1064   sql << ",18446744073709551615"
1065 end
select_with_sql_base() click to toggle source

Use WITH RECURSIVE instead of WITH if any of the CTEs is recursive

Calls superclass method
     # File lib/sequel/adapters/shared/mysql.rb
1096 def select_with_sql_base
1097   opts[:with].any?{|w| w[:recursive]} ? "WITH RECURSIVE " : super
1098 end
update_ignore_sql(sql) click to toggle source

MySQL supports UPDATE IGNORE

    # File lib/sequel/adapters/shared/mysql.rb
943 def update_ignore_sql(sql)
944   sql << " IGNORE" if opts[:update_ignore]
945 end
update_limit_sql(sql)
Alias for: limit_sql
uses_with_rollup?() click to toggle source

MySQL uses WITH ROLLUP syntax.

     # File lib/sequel/adapters/shared/mysql.rb
1101 def uses_with_rollup?
1102   true
1103 end