1. Dropping Clustered Tables
To drop a cluster, your schema must contain the cluster or you must have the DROP ANY CLUSTER system privilege. You do not have to have additional privileges to drop a cluster that contains tables, even if the clustered tables are not owned by the owner of the cluster.

Clustered tables can be dropped individually without affecting the table's cluster, other clustered tables, or the cluster index. A clustered table is dropped just as a non-clustered table is dropped--with the DROP TABLE statement.


--------------------------------------------------------------------------------
Note:
When you drop a single table from a cluster, Oracle deletes each row of the table individually. To maximize efficiency when you intend to drop an entire cluster, drop the cluster including all tables by using the DROP CLUSTER statement with the INCLUDING TABLES option. Drop an individual table from a cluster (using the DROP TABLE statement) only if you want the rest of the cluster to remain.  


Dropping Cluster Indexes
A cluster index can be dropped without affecting the cluster or its clustered tables. However, clustered tables cannot be used if there is no cluster index; you must re-create the cluster index to allow access to the cluster. Cluster indexes are sometimes dropped as part of the procedure to rebuild a fragmented cluster index.

To drop a cluster that contains no tables, and its cluster index, use the SQL DROP CLUSTER statement. For example, the following statement drops the empty cluster named EMP_DEPT:

2.DROP CLUSTER emp_dept;


If the cluster contains one or more clustered tables and you intend to drop the tables as well, add the INCLUDING TABLES option of the DROP CLUSTER statement, as follows:

DROP CLUSTER emp_dept INCLUDING TABLES;


If the INCLUDING TABLES option is not included and the cluster contains tables, an error is returned.

If one or more tables in a cluster contain primary or unique keys that are referenced by FOREIGN KEY constraints of tables outside the cluster, the cluster cannot be dropped unless the dependent FOREIGN KEY constraints are also dropped. This can be easily done using the CASCADE CONSTRAINTS option of the DROP CLUSTER statement, as shown in the following example:

DROP CLUSTER emp_dept INCLUDING TABLES CASCADE CONSTRAINTS;


Oracle returns an error if you do not use the CASCADE CONSTRAINTS option and constraints exist.


2. drop TYPE typename;

3.
ORA-02303 cannot drop or replace a type with type or table dependent(s)

Cause An attempt was made to drop or replace a type that has dependents.
Action Drop all type(s) and table(s) depending on the type, then retry the operation or use the FORCE option.