Class Sequel::SQL::StringExpression
In: lib/sequel/sql.rb
Parent: ComplexExpression

Subclass of ComplexExpression where the expression results in a text/string/varchar value in SQL.

Methods

like   sql_string  

Included Modules

StringMethods StringConcatenationMethods InequalityMethods

Constants

LIKE_MAP = {[true, true]=>:'~*', [true, false]=>:~, [false, true]=>:ILIKE, [false, false]=>:LIKE}   Map of [regexp, case_insenstive] to ComplexExpression operator symbol

Public Class methods

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 MySQL and PostgreSQL. Be aware that MySQL and PostgreSQL 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%'
  StringExpression.like(:a, 'a%', :case_insensitive=>true) # "a" ILIKE 'a%'
  StringExpression.like(:a, 'a%', /^a/i) # "a" LIKE 'a%' OR "a" ~* '^a'

[Source]

     # File lib/sequel/sql.rb, line 983
983:       def self.like(l, *ces)
984:         l, lre, lci = like_element(l)
985:         lci = (ces.last.is_a?(Hash) ? ces.pop : {})[:case_insensitive] ? true : lci
986:         ces.collect! do |ce|
987:           r, rre, rci = like_element(ce)
988:           BooleanExpression.new(LIKE_MAP[[lre||rre, lci||rci]], l, r)
989:         end
990:         ces.length == 1 ? ces.at(0) : BooleanExpression.new(:OR, *ces)
991:       end

Public Instance methods

Return self instead of creating a new object to save on memory.

[Source]

      # File lib/sequel/sql.rb, line 1007
1007:       def sql_string
1008:         self
1009:       end

[Validate]