SET SERVEROUT ON

CREATE OR REPLACE PROCEDURE gracefullyDropUser(v_username IN VARCHAR2) IS
l_cnt integer;
sqlStmt VARCHAR2(1000);
BEGIN
sqlStmt := 'alter user ' || v_username || ' account lock'; --锁住用户，防止其他新会话的连接
EXECUTE IMMEDIATE sqlStmt;
dbms_output.put_line(sqlStmt);
FOR x IN (SELECT * FROM v$session WHERE username = v_username) LOOP
sqlStmt := 'alter system disconnect session ''' || x.sid || ',' ||
x.serial# || ''' IMMEDIATE'; --循环disconnect每一个已存的session连接，并等待所有session被删除
EXECUTE IMMEDIATE sqlStmt;
dbms_output.put_line(sqlStmt);
END LOOP;

-- Wait until all sessions are disconnected forcely, check every 2 seconds
LOOP
SELECT COUNT(*) INTO l_cnt FROM v$session WHERE username = v_username;
EXIT WHEN l_cnt = 0;
dbms_lock.sleep(2);
dbms_output.put_line('hold on ...');
END LOOP;
sqlStmt := 'drop user ' || v_username || ' cascade'; --安全地删除数据库用户
EXECUTE IMMEDIATE sqlStmt;
dbms_output.put_line(sqlStmt);
END gracefullyDropUser;
/

execute gracefullyDropUser('AGILE');
alter user AGILE account lock
alter system disconnect session '12,97' IMMEDIATE
alter system disconnect session '20,11' IMMEDIATE
alter system disconnect session '141,118' IMMEDIATE
hold on ...
hold on ...
drop user AGILE cascade

PL/SQL procedure successfully completed.