Added support for conditions on Base.exists? (closes #5689) [josh@joshpeek.com]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@4651 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/CHANGELOG

@@ -1,5 +1,11 @@
 *SVN*
 
+* Added support for conditions on Base.exists? #5689 [josh@joshpeek.com]. Examples:
+
+    assert (Topic.exists?(:author_name => "David")) 
+ 	  assert (Topic.exists?(:author_name => "Mary", :approved => true)) 
+ 	  assert (Topic.exists?(["parent_id = ?", 1]))
+
 * Schema dumper quotes date :default values. [Dave Thomas]
 
 * Calculate sum with SQL, not Enumerable on HasManyThrough Associations. [Dan Peterson]

activerecord/lib/active_record/base.rb

@@ -423,10 +423,13 @@ module ActiveRecord #:nodoc:
       end
 
       # Returns true if the given +id+ represents the primary key of a record in the database, false otherwise.
+      # You can also pass a set of SQL conditions. 
       # Example:
       #   Person.exists?(5)
-      def exists?(id)
-        !find(:first, :conditions => ["#{primary_key} = ?", id]).nil? rescue false
+      #   Person.exists?(:name => "David")
+      def exists?(conditions)
+        conditions = ["#{primary_key} = ?", conditions] if conditions.is_a?(Fixnum)
+        !find(:first, :conditions => conditions).nil? rescue false
       end
 
       # Creates an object, instantly saves it as a record (if the validation permits it), and returns it. If the save

activerecord/test/finder_test.rb

@@ -21,6 +21,9 @@ class FinderTest < Test::Unit::TestCase
   
   def test_exists
     assert (Topic.exists?(1))
+    assert (Topic.exists?(:author_name => "David"))
+    assert (Topic.exists?(:author_name => "Mary", :approved => true))
+    assert (Topic.exists?(["parent_id = ?", 1]))
     assert !(Topic.exists?(45))
     assert !(Topic.exists?("foo"))
     assert !(Topic.exists?([1,2]))