|Oracle® Database SQL Language Reference
11g Release 2 (11.2)
Part Number E17118-03
Object types are defined using PL/SQL. Please refer to Oracle Database PL/SQL Language Reference for complete information on creating, altering, and dropping object types.
The object type, varray, or nested table type must be in your own schema or you must have the
TYPE system privilege.
Specify the schema containing the type. If you omit
schema, then Oracle Database assumes the type is in your own schema.
Specify the name of the object, varray, or nested table type to be dropped. You can drop only types with no type or table dependencies.
type_name is a supertype, then this statement will fail unless you also specify
FORCE. If you specify
FORCE, then the database invalidates all subtypes depending on this supertype.
type_name is a statistics type, then this statement will fail 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 is an object type that has been 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 will be unable to disassociate
type_name from the statistics type, and this statement will fail.
type_name is an implementation type for an indextype, then the indextype will be marked
type_name has a public synonym defined on it, then the database will also drop the synonym.
Unless you specify
FORCE, you can drop only object types, nested tables, or varray types that are standalone schema objects with no dependencies. This is the default behavior.
See Also:CREATE INDEXTYPE
FORCE to drop the type even if it has dependent database objects. Oracle Database marks
UNUSED all columns dependent on the type to be dropped, and those columns become inaccessible.
Caution:Oracle does not recommend that you specify
FORCEto drop object types with dependencies. This operation is not recoverable and could cause the data in the dependent tables or columns to become inaccessible.
If you specify
VALIDATE when dropping a type, then Oracle Database checks for stored instances of this type within 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.
Dropping an Object Type: Example
The following statement removes object type
person_t. See Oracle Database PL/SQL Language Reference for the example that creates this object type. Any columns that are dependent on person_t are marked
UNUSED and become inaccessible.
DROP TYPE person_t FORCE;