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 090c480e4b..2dc9fb2513 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -31,6 +31,7 @@ module ActiveRecord
         string:      { name: "varchar", limit: 255 },
         text:        { name: "text" },
         integer:     { name: "int", limit: 4 },
+        bigint:      { name: "bigint" },
         float:       { name: "float", limit: 24 },
         decimal:     { name: "decimal" },
         datetime:    { name: "datetime" },
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index 354d2eeb97..74b36e21ae 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -125,6 +125,7 @@ module ActiveRecord
         string:      { name: "character varying" },
         text:        { name: "text" },
         integer:     { name: "integer", limit: 4 },
+        bigint:      { name: "bigint" },
         float:       { name: "float" },
         decimal:     { name: "decimal" },
         datetime:    {}, # set dynamically based on datetime_type