exists?
exists?(id = false)Returns true if a record exists in the table that matches the id or conditions given, or false otherwise. The argument can take five forms:
-
Integer - Finds the record with this primary key.
-
String - Finds the record with a primary key corresponding to this string (such as '5').
-
Array - Finds the record that matches these find-style conditions (such as ['color = ?', 'red']).
-
Hash - Finds the record that matches these find-style conditions (such as {:color => 'red'}).
-
No args - Returns false if the table is empty, true otherwise.
For more information about specifying conditions as a Hash or Array, see the Conditions section in the introduction to ActiveRecord::Base.
Note: You can’t pass in a condition as a string (like name = 'Jamie'), since it would be sanitized and then queried against the primary key column, like id = 'name = \'Jamie\''.
Examples
Person.exists?(5) Person.exists?('5') Person.exists?(:name => "David") Person.exists?(['name LIKE ?', "%#{query}%"]) Person.exists?
1Note
More AREL compliant style is also possible
==== Code example
Person.where(:name => 'David').exists?