1 files changed, 27 insertions, 22 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
index c9180f64db..503b09d1fc 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -667,7 +667,7 @@ module ActiveRecord
       #   remove_reference(:products, :user, index: true, foreign_key: true)
       #
       def remove_reference(table_name, ref_name, options = {})
-        remove_foreign_key table_name, ref_name if options[:foreign_key]
+        remove_foreign_key table_name, ref_name.to_s.pluralize if options[:foreign_key]
 
         remove_column(table_name, "#{ref_name}_id")
         remove_column(table_name, "#{ref_name}_type") if options[:polymorphic]
@@ -757,21 +757,7 @@ module ActiveRecord
       def remove_foreign_key(from_table, options_or_to_table = {})
         return unless supports_foreign_keys?
 
-        if options_or_to_table.is_a?(Hash)
-          options = options_or_to_table
-        else
-          options = { column: foreign_key_column_for(options_or_to_table) }
-        end
-
-        fk_name_to_delete = options.fetch(:name) do
-          fk_to_delete = foreign_keys(from_table).detect {|fk| fk.column == options[:column].to_s }
-
-          if fk_to_delete
-            fk_to_delete.name
-          else
-            raise ArgumentError, "Table '#{from_table}' has no foreign key on column '#{options[:column]}'"
-          end
-        end
+        fk_name_to_delete = foreign_key_for!(from_table, options_or_to_table).name
 
         at = create_alter_table from_table
         at.drop_foreign_key fk_name_to_delete
@@ -779,6 +765,31 @@ module ActiveRecord
         execute schema_creation.accept(at)
       end
 
+      # Checks to see if a foreign key exists on a table for a given foreign key definition.
+      #
+      #   # Check a foreign key exists
+      #   foreign_key_exists?(:accounts, :branches)
+      #
+      #   # Check a foreign key on specified column exists
+      #   foreign_key_exists?(:accounts, column: :owner_id)
+      #
+      #   # Check a foreign key with a custom name exists
+      #   foreign_key_exists?(:accounts, name: "special_fk_name")
+      #
+      def foreign_key_exists?(from_table, options_or_to_table = {})
+        foreign_key_for(from_table, options_or_to_table).present?
+      end
+
+      def foreign_key_for(from_table, options_or_to_table = {}) # :nodoc:
+        return unless supports_foreign_keys?
+        foreign_keys(from_table).detect {|fk| fk.defined_for? options_or_to_table }
+      end
+
+      def foreign_key_for!(from_table, options_or_to_table = {}) # :nodoc:
+        foreign_key_for(from_table, options_or_to_table) or \
+          raise ArgumentError, "Table '#{from_table}' has no foreign key for #{options_or_to_table}"
+      end
+
       def foreign_key_column_for(table_name) # :nodoc:
         "#{table_name.to_s.singularize}_id"
       end
@@ -840,12 +851,6 @@ module ActiveRecord
               raise ArgumentError, "Error adding decimal column: precision cannot be empty if scale is specified"
             end
 
-          elsif [:datetime, :time].include?(type) && precision ||= native[:precision]
-            if (0..6) === precision
-              column_type_sql << "(#{precision})"
-            else
-              raise(ActiveRecordError, "No #{native[:name]} type has precision of #{precision}. The allowed range of precision is from 0 to 6")
-            end
           elsif (type != :primary_key) && (limit ||= native.is_a?(Hash) && native[:limit])
             column_type_sql << "(#{limit})"
           end