fk: `foreign_keys`, `add_foreign_key` and `remove_foreign_key` for MySQL

2 files changed, 21 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
index a9b3e9cfb9..b132543332 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
@@ -25,6 +25,20 @@ module ActiveRecord
     class ChangeColumnDefinition < Struct.new(:column, :type, :options) #:nodoc:
     end
 
+    class ForeignKeyDefinition < Struct.new(:from_table, :to_table, :options)
+      def name
+        options[:name]
+      end
+
+      def column
+        options[:column]
+      end
+
+      def primary_key
+        options[:primary_key]
+      end
+    end
+
     # Represents the schema of an SQL table in an abstract way. This class
     # provides methods for manipulating the schema representation.
     #
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 22823a8c58..55e3fb4477 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -625,6 +625,13 @@ module ActiveRecord
       end
       alias :add_belongs_to :add_reference
 
+      def foreign_key_name(table_name, options)
+        options.fetch(:name) do
+          column_name = options.fetch(:column)
+          "#{table_name}_#{column_name}_fk"
+        end
+      end
+
       # Removes the reference(s). Also removes a +type+ column if one exists.
       # <tt>remove_reference</tt>, <tt>remove_references</tt> and <tt>remove_belongs_to</tt> are acceptable.
       #