在ORACLE数据中修改会话级临时表时，有可能会遇到ORA-14550错误，那么为什么会话级全局临时表会报ORA-14450错误呢，如下所示，我们先从一个小小案例入手：
案例1：
SQL> CREATE GLOBAL TEMPORARY TABLE TEMP_TEST
2 (
3 NAME VARCHAR2(12)
4 ) ON COMMIT PRESERVE ROWS;
Table created.
SQL> INSERT INTO TEMP_TEST VALUES('kerry');
1 row created.
SQL> COMMIT;
Commit complete.
SQL> ALTER TABLE TEMP_TEST ADD SEX NUMBER(1) ;
ALTER TABLE TEMP_TEST ADD SEX NUMBER(1)
*
ERROR at line 1:
ORA-14450: attempt to access a transactional temp table already in use
如上所示，修改会话级临时表时遇到了ORA-14450错误，那么有哪些解决方法呢？ 这时需要断开会话或执行TRUNCATE语句：
SQL> TRUNCATE TABLE TEMP_TEST;
Table truncated.
SQL> ALTER TABLE TEMP_TEST ADD SEX NUMBER(1) ;
Table altered.
SQL>
如下所示，我们模拟一个会话在操作临时表TEMP_TEST， 另外一个会话准备修改它，如下所示（实际场景可能更复杂，可能涉及多个会话而不是仅仅两个会话）
会话1：
SQL> SET SQLPROMPT "SQLSESSION 1 >"
SQLSESSION 1 >CREATE GLOBAL TEMPORARY TABLE TEMP_TEST
2 (
3 NAME VARCHAR2(12)
4 ) ON COMMIT PRESERVE ROWS;
Table created.
SQLSESSION 1 >INSERT INTO TEMP_TEST VALUES('kerry');
1 row created.
SQLSESSION 1 >COMMIT;
Commit complete.
SQLSESSION 1 >
会话2：:
SQL> SET SQLPROMPT "SESSION 2 >"
SESSION 2 >ALTER TABLE TEMP_TEST ADD SEX NUMBER(1) ;
ALTER TABLE TEMP_TEST ADD SEX NUMBER(1)
*
ERROR at line 1:
ORA-14450: attempt to access a transactional temp table already in use
SESSION 2 >
那么此时，会话1是其它用户登录的。比如应用程序等，你不可能要求所有会话都去执行TRUNCATE操作，这个时候该怎么处理呢？
此时你可以使用下面步骤解决这个问题。
Step 1、以sys或system登录数据库，先从DBA_OBJECTS中查询到该表的OBJECT_ID:
SELECT OWNER, OBJECT_ID,OBJECT_TYPE
FROM DBA_OBJECTS
WHERE OBJECT_NAME=&OBJECT_NAME AND OBJECT_TYPE ='TABLE';
Step 2、根据查到的OBJECT_ID知道使用该表的SESSION：
SELECT ADDR, KADDR, SID,LMODE FROM V$LOCK WHERE ID1=&OBJECT_ID;
Step 3、通过下面SQL找到对应的会话并生成KILL SESSION的执行语句
SET COL kill_session FOR A80;
select a.sid, a.serial#,a.status,
a.paddr, 'alter system kill session '''
|| a.sid || ',' || a.serial#
|| ''' immediate;' AS kill_session
FROM v$session a
WHERE a.sid in (select sid from v$enqueue_lock t where t.type='TO')
and a.sid=&sid;
Step 4、查看会话状态，并执行ALTER SYSTEM KILL SESSION语句杀掉这些进程:
具体操作步骤，如下截图所示：
原因: 查看ORA-14450的错误，你可以看到如下信息：
[oracle@oracle-server ~]$ oerr ora 14450
14450, 00000, "attempt to access a transactional temp table already in use"
// *Cause: An attempt was made to access a transactional temporary table that
// has been already populated by a concurrent transaction of the same
// session.
// *Action: do not attempt to access the temporary table until the
// concurrent transaction has committed or aborted.