DROP TYPE Statement

The DROP TYPE statement drops the specification and body of an ADT, varray type, or nested table type.

Topics:

• Prerequisites

• Syntax

• Semantics

• Example

• Related Topics

Prerequisites

The ADT, varray type, or nested table type must be in your own schema or you must have the DROP ANY TYPE system privilege.

Syntax

drop_type::=

Semantics

schema

The name of the schema containing the type. The default is your own schema.

type_name

The name of the object, varray, or nested table type to be dropped. You can drop only types with no type or table dependencies.

If type_name is a supertype, then this statement fails unless you also specify FORCE. If you specify FORCE, then the database invalidates all subtypes depending on this supertype.

If type_name is a statistics type, then this statement fails unless you also specify FORCE. If you specify FORCE, then the database first disassociates all objects that are associated with type_name and then drops type_name.

If type_name is an ADT that is associated with a statistics type, then the database first attempts to disassociate type_name from the statistics type and then drops type_name. However, if statistics have been collected using the statistics type, then the database cannot disassociate type_name from the statistics type, and this statement fails.

If type_name is an implementation type for an index type, then the index type is marked INVALID.

If type_name has a public synonym defined on it, then the database also drops the synonym.

Unless you specify FORCE, you can drop only types that are standalone schema objects with no dependencies. This is the default behavior.

FORCE

Drops the type even if it has dependent database objects. The database marks UNUSED all columns dependent on the type to be dropped, and those columns become inaccessible.

VALIDATE

Causes the database to check for stored instances of this type in substitutable columns of any of its supertypes. If no such instances are found, then the database completes the drop operation.

This clause is meaningful only for subtypes. Oracle recommends the use of this option to safely drop subtypes that do not have any explicit type or table dependencies.

Example

Dropping an ADT: Example This statement removes the ADT person_t. See "Type Hierarchy Example" for the example that creates this ADT. Any columns that are dependent on person_t are marked UNUSED and become inaccessible.

DROP TYPE person_t FORCE;

Related Topics

• "ALTER TYPE Statement"

• "CREATE TYPE Statement"

• "CREATE TYPE BODY Statement"