module Sequel::MySQL::DatasetMethods
Dataset methods shared by datasets that use MySQL databases.
Constants
- APOS
- APOS_RE
- BACKSLASH
- BACKSLASH_RE
- BACKTICK
- BACKTICK_RE
- BINARY
- BLOB_START
- BOOL_FALSE
- BOOL_TRUE
- CAST_BITCOMP_CLOSE
- CAST_BITCOMP_OPEN
- COMMA
- COMMA_SEPARATOR
- CONCAT
- CURRENT_TIMESTAMP_56
- DOUBLE_APOS
- DOUBLE_BACKTICK
- EMPTY_BLOB
- EMPTY_COLUMNS
- EMPTY_VALUES
- EQ
- EQ_VALUES
- ESCAPE
- EXPLAIN
- EXPLAIN_EXTENDED
- FOR_SHARE
- FROM
- GROUP_BY
- HSTAR
- IGNORE
- LIKE
- LIMIT
- MATCH_AGAINST
- MATCH_AGAINST_BOOLEAN
- NATURAL_LEFT_JOIN
- NON_SQL_OPTIONS
- NOT_SPACE
- ONLY_OFFSET
Comes directly from MySQL's documentation, used for queries with limits without offsets
- ON_DUPLICATE_KEY_UPDATE
- PAREN_CLOSE
- PAREN_OPEN
- QUAD_BACKSLASH
- REGEXP
- SPACE
- SQL_CALC_FOUND_ROWS
- STRAIGHT_JOIN
- WITH_ROLLUP
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
# File lib/sequel/adapters/shared/mysql.rb, line 700 def calc_found_rows clone(:calc_found_rows => true) end
MySQL specific syntax for LIKE/REGEXP searches, as well as string concatenation.
# File lib/sequel/adapters/shared/mysql.rb, line 640 def complex_expression_sql_append(sql, op, args) case op when :IN, :"NOT IN" ds = args.at(1) if ds.is_a?(Sequel::Dataset) && ds.opts[:limit] super(sql, op, [args.at(0), ds.from_self]) else super end when :~, :'!~', :'~*', :'!~*', :LIKE, :'NOT LIKE', :ILIKE, :'NOT ILIKE' sql << PAREN_OPEN literal_append(sql, args.at(0)) sql << SPACE sql << 'NOT ' if [:'NOT LIKE', :'NOT ILIKE', :'!~', :'!~*'].include?(op) sql << ([:~, :'!~', :'~*', :'!~*'].include?(op) ? REGEXP : LIKE) sql << SPACE sql << BINARY if [:~, :'!~', :LIKE, :'NOT LIKE'].include?(op) literal_append(sql, args.at(1)) if [:LIKE, :'NOT LIKE', :ILIKE, :'NOT ILIKE'].include?(op) sql << ESCAPE literal_append(sql, BACKSLASH) end sql << PAREN_CLOSE when :'||' if args.length > 1 sql << CONCAT array_sql_append(sql, args) else literal_append(sql, args.at(0)) end when :'B~' sql << CAST_BITCOMP_OPEN literal_append(sql, args.at(0)) sql << CAST_BITCOMP_CLOSE else super end end
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.
# File lib/sequel/adapters/shared/mysql.rb, line 683 def constant_sql_append(sql, constant) if constant == :CURRENT_TIMESTAMP && supports_timestamp_usecs? sql << CURRENT_TIMESTAMP_56 else super end end
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, line 712 def delete_from(*tables) clone(:delete_from=>tables) end
Use GROUP BY instead of DISTINCT ON if arguments are provided.
# File lib/sequel/adapters/shared/mysql.rb, line 692 def distinct(*args) args.empty? ? super : group(*args) end
Return the results of an EXPLAIN query as a string. Options:
# File lib/sequel/adapters/shared/mysql.rb, line 718 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
Adds full text filter
# File lib/sequel/adapters/shared/mysql.rb, line 733 def full_text_search(cols, terms, opts = OPTS) where(full_text_sql(cols, terms, opts)) end
MySQL specific full text search syntax.
# File lib/sequel/adapters/shared/mysql.rb, line 738 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
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, line 772 def insert_ignore clone(:insert_ignore=>true) 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.
# File lib/sequel/adapters/shared/mysql.rb, line 745 def join_table(type, table, expr=nil, opts=OPTS, &block) type = :inner if (type == :cross) && !expr.nil? raise(Sequel::Error, "MySQL doesn't support FULL OUTER JOIN") if type == :full_outer super(type, table, expr, opts, &block) end
Transforms :natural_inner to NATURAL LEFT JOIN and straight to STRAIGHT_JOIN.
# File lib/sequel/adapters/shared/mysql.rb, line 753 def join_type_sql(join_type) case join_type when :straight STRAIGHT_JOIN when :natural_inner NATURAL_LEFT_JOIN else super end 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. 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, line 805 def on_duplicate_key_update(*args) clone(:on_duplicate_key_update => args) end
MySQL uses the nonstandard ` (backtick) for quoting identifiers.
# File lib/sequel/adapters/shared/mysql.rb, line 810 def quoted_identifier_append(sql, c) sql << BACKTICK << c.to_s.gsub(BACKTICK_RE, DOUBLE_BACKTICK) << BACKTICK end
MySQL does not support derived column lists
# File lib/sequel/adapters/shared/mysql.rb, line 815 def supports_derived_column_lists? false end
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, line 821 def supports_distinct_on? true end
MySQL supports GROUP BY WITH ROLLUP (but not CUBE)
# File lib/sequel/adapters/shared/mysql.rb, line 826 def supports_group_rollup? true end
MySQL does not support INTERSECT or EXCEPT
# File lib/sequel/adapters/shared/mysql.rb, line 831 def supports_intersect_except? false end
MySQL supports modifying joined datasets
# File lib/sequel/adapters/shared/mysql.rb, line 841 def supports_modifying_joins? true end
MySQL's DISTINCT ON emulation using GROUP BY does not respect the queries ORDER BY clause.
# File lib/sequel/adapters/shared/mysql.rb, line 847 def supports_ordered_distinct_on? false end
MySQL supports pattern matching via regular expressions
# File lib/sequel/adapters/shared/mysql.rb, line 852 def supports_regexp? true 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.
# File lib/sequel/adapters/shared/mysql.rb, line 859 def supports_timestamp_usecs? db.supports_timestamp_usecs? 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
# File lib/sequel/adapters/shared/mysql.rb, line 869 def update_ignore clone(:update_ignore=>true) end
Private Instance Methods
Allow update and delete for limited datasets, unless there is an offset.
# File lib/sequel/adapters/shared/mysql.rb, line 876 def check_not_limited!(type) super if type == :truncate || @opts[:offset] end
Consider the first table in the joined dataset is the table to delete from, but include the others for the purposes of selecting rows.
# File lib/sequel/adapters/shared/mysql.rb, line 882 def delete_from_sql(sql) if joined_dataset? sql << SPACE tables = @opts[:delete_from] || @opts[:from][0..0] source_list_append(sql, tables) sql << FROM source_list_append(sql, @opts[:from]) select_join_sql(sql) else super end end
MySQL supports INSERT … ON DUPLICATE KEY UPDATE
# File lib/sequel/adapters/shared/mysql.rb, line 916 def insert_on_duplicate_key_update_sql(sql) if update_cols = opts[:on_duplicate_key_update] update_vals = nil if update_cols.empty? update_cols = columns elsif update_cols.last.is_a?(Hash) update_vals = update_cols.last update_cols = update_cols[0..-2] end sql << ON_DUPLICATE_KEY_UPDATE c = false co = COMMA values = EQ_VALUES endp = PAREN_CLOSE update_cols.each do |col| sql << co if c quote_identifier_append(sql, col) sql << values quote_identifier_append(sql, col) sql << endp c ||= true end if update_vals eq = EQ update_vals.map do |col,v| sql << co if c quote_identifier_append(sql, col) sql << eq literal_append(sql, v) c ||= true end end end end
MySQL doesn't use the standard DEFAULT VALUES for empty values.
# File lib/sequel/adapters/shared/mysql.rb, line 954 def insert_values_sql(sql) values = opts[:values] if values.is_a?(Array) && values.empty? sql << EMPTY_VALUES else super end end
MySQL allows a LIMIT in DELETE and UPDATE statements.
# File lib/sequel/adapters/shared/mysql.rb, line 964 def limit_sql(sql) if l = @opts[:limit] sql << LIMIT literal_append(sql, l) end end
MySQL uses a preceding X for hex escaping strings
# File lib/sequel/adapters/shared/mysql.rb, line 974 def literal_blob_append(sql, v) if v.empty? sql << EMPTY_BLOB else sql << BLOB_START << v.unpack(HSTAR).first end end
Use 0 for false on MySQL
# File lib/sequel/adapters/shared/mysql.rb, line 983 def literal_false BOOL_FALSE end
Raise error for infinitate and NaN values
# File lib/sequel/adapters/shared/mysql.rb, line 988 def literal_float(v) if v.infinite? || v.nan? raise InvalidValue, "Infinite floats and NaN values are not valid on MySQL" else super end end
Use 1 for true on MySQL
# File lib/sequel/adapters/shared/mysql.rb, line 1002 def literal_true BOOL_TRUE end
MySQL supports multiple rows in INSERT.
# File lib/sequel/adapters/shared/mysql.rb, line 1007 def multi_insert_sql_strategy :values end
MySQL specific SQL_CALC_FOUND_ROWS option
# File lib/sequel/adapters/shared/mysql.rb, line 1028 def select_calc_found_rows_sql(sql) sql << SQL_CALC_FOUND_ROWS if opts[:calc_found_rows] end
Support FOR SHARE locking when using the :share lock style.
# File lib/sequel/adapters/shared/mysql.rb, line 1023 def select_lock_sql(sql) @opts[:lock] == :share ? (sql << FOR_SHARE) : super end
# File lib/sequel/adapters/shared/mysql.rb, line 1016 def select_only_offset_sql(sql) sql << LIMIT literal_append(sql, @opts[:offset]) sql << ONLY_OFFSET end
MySQL uses WITH ROLLUP syntax.
# File lib/sequel/adapters/shared/mysql.rb, line 1033 def uses_with_rollup? true end