Drop user ORA-00942, ORA-00604, ORA-06512

[xiaomao]

Well, we can prove this by turn on the trace.

alter session set sql_trace=true;

drop user a;

In the tracefile, you should be able to see the statement like

DELETE FROM SDO_GEOM_METADATA_TABLE
WHERE
'"'||SDO_OWNER||'"' = '"A"'

You can check your database whether table SDO_GEOM_METADATA_TABLE exists or not.

SQL> select owner from dba_tables where table_name='SDO_GEOM_METADATA_TABLE';

OWNER
-----------------------
MDSYS

In your case, you are supposed to see some error messages like

ORA-00942: table or view does not exist
Current SQL statement for this session:
DELETE FROM SDO_GEOM_METADATA_TABLE WHERE '"'||SDO_OWNER||'"' = '"A"';

Here the error ORA-00942 refer to table SDO_GEOM_METADATA_TABLE. This is the reason why you need to install Oralce Spatial as the missing table is owned by MDSYS.

Make sure you install Oralce Spatial correctly and table SDO_GEOM_METADATA_TABLE
does exist in your database.