Class: Sequel::SQL::StringExpression
- Inherits:
-
ComplexExpression
- Object
- Expression
- ComplexExpression
- Sequel::SQL::StringExpression
- Includes:
- InequalityMethods, StringConcatenationMethods, StringMethods
- Defined in:
- lib/sequel/sql.rb
Overview
Subclass of ComplexExpression
where the expression results in a text/string/varchar value in SQL.
Constant Summary collapse
- LIKE_MAP =
Map of [regexp, case_insenstive] to
ComplexExpression
operator symbol {[true, true]=>:'~*', [true, false]=>:~, [false, true]=>:ILIKE, [false, false]=>:LIKE}.freeze
Constants inherited from ComplexExpression
ComplexExpression::ASSOCIATIVE_OPERATORS, ComplexExpression::BITWISE_OPERATORS, ComplexExpression::BOOLEAN_OPERATOR_METHODS, ComplexExpression::CONSTANT_INVERSIONS, ComplexExpression::CUSTOM_EXPRESSIONS, ComplexExpression::EQUALITY_OPERATORS, ComplexExpression::INEQUALITY_OPERATORS, ComplexExpression::IN_OPERATORS, ComplexExpression::IS_OPERATORS, ComplexExpression::LIKE_OPERATORS, ComplexExpression::MATHEMATICAL_OPERATORS, ComplexExpression::N_ARITY_OPERATORS, ComplexExpression::ONE_ARITY_OPERATORS, ComplexExpression::OPERTATOR_INVERSIONS, ComplexExpression::REGEXP_OPERATORS, ComplexExpression::TWO_ARITY_OPERATORS
Instance Attribute Summary
Attributes inherited from ComplexExpression
Class Method Summary collapse
-
.like(l, *ces) ⇒ Object
Creates a SQL pattern match exprssion.
Instance Method Summary collapse
-
#sql_string ⇒ Object
Return self instead of creating a new object to save on memory.
Methods included from StringConcatenationMethods
Methods included from StringMethods
#escaped_ilike, #escaped_like, #ilike, #like
Methods inherited from ComplexExpression
#initialize, #sql_boolean, #sql_number
Methods included from SubscriptMethods
Methods included from PatternMatchMethods
Methods included from OrderMethods
Methods included from CastMethods
#cast, #cast_numeric, #cast_string
Methods included from AliasMethods
Methods inherited from Expression
#==, attr_reader, #clone, #eql?, #hash, inherited, #inspect
Constructor Details
This class inherits a constructor from Sequel::SQL::ComplexExpression
Class Method Details
.like(l, *ces) ⇒ Object
Creates a SQL pattern match exprssion. left (l) is the SQL string we are matching against, and ces are the patterns we are matching. The match succeeds if any of the patterns match (SQL OR).
If a regular expression is used as a pattern, an SQL regular expression will be used, which is currently only supported on some databases. Be aware that SQL regular expression syntax is similar to ruby regular expression syntax, but it not exactly the same, especially for advanced regular expression features. Sequel just uses the source of the ruby regular expression verbatim as the SQL regular expression string.
If any other object is used as a regular expression, the SQL LIKE operator will be used, and should be supported by most databases.
The pattern match will be case insensitive if the last argument is a hash with a key of :case_insensitive that is not false or nil. Also, if a case insensitive regular expression is used (//i), that particular pattern which will always be case insensitive.
StringExpression.like(:a, 'a%') # ("a" LIKE 'a%' ESCAPE '\')
StringExpression.like(:a, 'a%', case_insensitive: true) # ("a" ILIKE 'a%' ESCAPE '\')
StringExpression.like(:a, 'a%', /^a/i) # (("a" LIKE 'a%' ESCAPE '\') OR ("a" ~* '^a'))
1769 1770 1771 1772 1773 1774 1775 1776 1777 |
# File 'lib/sequel/sql.rb', line 1769 def self.like(l, *ces) l, lre, lci = like_element(l) lci = (ces.last.is_a?(Hash) ? ces.pop : OPTS)[:case_insensitive] ? true : lci ces.map! do |ce| r, rre, rci = like_element(ce) BooleanExpression.new(LIKE_MAP[[lre||rre, lci||rci]], l, r) end ces.length == 1 ? ces[0] : BooleanExpression.new(:OR, *ces) end |
Instance Method Details
#sql_string ⇒ Object
Return self instead of creating a new object to save on memory.
1793 1794 1795 |
# File 'lib/sequel/sql.rb', line 1793 def sql_string self end |