How to delete schema in oracle

In Oracle, you can use the drop statement to delete the schema. The syntax is "drop user username cascade;"; the drop statement is used to delete the structure of the table, including the schema. The schema is a collection of database objects and can also be understood as user.

The operating environment of this tutorial: Windows 10 system, Oracle 11g version, Dell G3 computer.

How to delete schema in oracle

The syntax for deleting schema is as follows:

drop user username cascade;

The example is as follows:

1 )View the user's default table space and temporary table space

set lines 300
col username for a30
select username ,default_tablespace,TEMPORARY_TABLESPACE from dba_users where username='MESPRD';
-----------------------------------
USERNAME   DEFAULT_TABLESPACE     TEMPORAR    Y_TABLESPACE
MESPRD    HTTBS_MESPRD                        TEMP

2)View the user's permissions and roles

select privilege from dba_sys_privs where grantee='SYSADM'
union
select privilege from dba_sys_privs where grantee in (select granted_role from dba_role_privs where grantee='MESPRD' );
-----------------------------------
PRIVILEGE
CREATE CLUSTER
CREATE INDEXTYPE
CREATE OPERATOR
CREATE PROCEDURE
CREATE SEQUENCE
CREATE SESSION
CREATE TABLE
CREATE TRIGGER
CREATE TYPE

9 rows have been selected.

3) Get the script to grant user permissions

select 'grant '||privilege||' to SYSADM;' from (select privilege from dba_sys_privs where grantee='SYSADM'
union
select privilege from dba_sys_privs where grantee in (select granted_role from dba_role_privs where grantee='SYSADM' ));

4) Execute the script to get the script to delete the object under the schema mesprd is the schema to be deleted

connect mesprd/MESPRD
spool E:\app\Administrator\del_mesprd.sql;
select 'alter table '||table_name||' drop constraint '||constraint_name||' ;' from user_constraints where constraint_type='R';
select 'truncate table '||table_name ||';' from user_tables;
select 'drop table '||table_name ||' purge;' from user_tables;
select 'drop index '||index_name ||';' from user_indexes;
select 'drop view ' ||view_name||';' from user_views;
select 'drop sequence ' ||sequence_name||';' from user_sequences;
select 'drop function ' ||object_name||';'  from user_objects  where object_type='FUNCTION';
select 'drop procedure '||object_name||';' from user_objects  where object_type='PROCEDURE';
select 'drop package '|| object_name||';' from user_objects  where object_type='PACKAGE';
select 'drop database link '|| object_name||';' from user_objects  where object_type='DATABASE LINK';
spool off;

5) sqlplus Connect to the schema and execute the script obtained above

Check the objects under the schema before execution, and check the objects under the schema again after execution

@？\E:\app\Administrator\del_mesprd.sql;
SQL> select object_type,count(*) from user_objects group by object_type;

6) Kill the connected database session

select 'alter system kill session '''||sid||','||serial#||''' immediate;' from v$session where username='MESPRD';

7) Delete the schema

drop user MESPRD cascade;

Recommended tutorial: "Oracle Video Tutorial"

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