class Sequel::SQL::StringExpression
Subclass of ComplexExpression
where the expression results in a text/string/varchar value in SQL
.
Constants
- LIKE_MAP
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 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'))
# File lib/sequel/sql.rb 1768 def self.like(l, *ces) 1769 l, lre, lci = like_element(l) 1770 lci = (ces.last.is_a?(Hash) ? ces.pop : OPTS)[:case_insensitive] ? true : lci 1771 ces.map! do |ce| 1772 r, rre, rci = like_element(ce) 1773 BooleanExpression.new(LIKE_MAP[[lre||rre, lci||rci]], l, r) 1774 end 1775 ces.length == 1 ? ces[0] : BooleanExpression.new(:OR, *ces) 1776 end
Public Instance Methods
Return self instead of creating a new object to save on memory.
# File lib/sequel/sql.rb 1792 def sql_string 1793 self 1794 end