MySQL: Raise ActiveRecord::InvalidForeignKey for foreign-key constraint violations on delete

2 files changed, 4 insertions, 2 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
index 284b38ed7b..9de8242a58 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -619,6 +619,7 @@ module ActiveRecord
         ER_DUP_ENTRY            = 1062
         ER_NOT_NULL_VIOLATION   = 1048
         ER_DO_NOT_HAVE_DEFAULT  = 1364
+        ER_ROW_IS_REFERENCED_2  = 1451
         ER_NO_REFERENCED_ROW_2  = 1452
         ER_DATA_TOO_LONG        = 1406
         ER_OUT_OF_RANGE         = 1264
@@ -633,7 +634,7 @@ module ActiveRecord
           case error_number(exception)
           when ER_DUP_ENTRY
             RecordNotUnique.new(message)
-          when ER_NO_REFERENCED_ROW_2
+          when ER_ROW_IS_REFERENCED_2, ER_NO_REFERENCED_ROW_2
             InvalidForeignKey.new(message)
           when ER_CANNOT_ADD_FOREIGN
             mismatched_foreign_key(message)
diff --git a/activerecord/lib/active_record/errors.rb b/activerecord/lib/active_record/errors.rb
index c2a180c939..f61bc7b9e8 100644
--- a/activerecord/lib/active_record/errors.rb
+++ b/activerecord/lib/active_record/errors.rb
@@ -111,7 +111,8 @@ module ActiveRecord
   class RecordNotUnique < WrappedDatabaseException
   end
 
-  # Raised when a record cannot be inserted or updated because it references a non-existent record.
+  # Raised when a record cannot be inserted or updated because it references a non-existent record,
+  # or when a record cannot be deleted because a parent record references it.
   class InvalidForeignKey < WrappedDatabaseException
   end