self.exists?(id_or_conditions = {}) — ActiveRecord::Base

self.exists?(id_or_conditions = {})

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?

Parameters

id_or_conditions opt = {}

Source

# File activerecord/lib/active_record/base.rb, line 693
      def exists?(id_or_conditions = {})
        find_initial(
          :select => "#{quoted_table_name}.#{primary_key}",
          :conditions => expand_id_conditions(id_or_conditions)) ? true : false
      end

Defined in activerecord/lib/active_record/base.rb line 693 · View on GitHub · Improve this page · Find usages on GitHub

Defined in ActiveRecord::Base

Signature

Examples

Parameters