# User-defined types

Derby allows you to create user-defined types. A user-defined type is a serializable Java class whose instances are stored in columns. The class must implement the java.io.Serializable interface.

For information on creating and removing types, see CREATE TYPE statement and DROP TYPE statement. See GRANT statement and REVOKE statement for information on usage privileges for types.

For information on writing the Java classes that implement user-defined types, see "Programming user-defined types" in the Java DB Developer's Guide.

Parent topic: Data types