临时表和专用临时表

创建全局临时表
ON COMMIT DELETE ROWS子句指示应在事务提交时或会话结束时删除数据
CREATE GLOBAL TEMPORARY TABLE lh_temp_table (
id NUMBER,
description VARCHAR2(20)
)
ON COMMIT DELETE ROWS;

INSERT INTO lh_temp_table VALUES (1, ‘ONE’);


SELECT COUNT() FROM lh_temp_table;

提交后就没有数据了
COMMIT;

SELECT COUNT() FROM lh_temp_table;


ON COMMIT PRESERVE ROWS子句指示行应在事务结束后继续存在。它们只会在会话结束时被删除。
CREATE GLOBAL TEMPORARY TABLE my_temp_table (
id NUMBER,
description VARCHAR2(20)
)
ON COMMIT PRESERVE ROWS;

INSERT INTO my_temp_table VALUES (1, ‘ONE’);
COMMIT;


SELECT COUNT() FROM my_temp_table;

重新连接后，数据才会没有的。


查看数据没有了
SELECT COUNT() FROM my_temp_table;

全局临时表和撤消
DROP TABLE my_temp_table PURGE;

CREATE TABLE my_temp_table (
id NUMBER,
description VARCHAR2(20)
);

INSERT INTO my_temp_table
WITH data AS (
SELECT 1 AS id
FROM dual
CONNECT BY level < 10000
)
SELECT rownum, TO_CHAR(rownum)
FROM data a, data b
WHERE rownum <= 1000000;

查看插入的数据


使用的撤消
SELECT t.used_ublk,
t.used_urec
FROM v$transactiont,v$session s
WHERE s.saddr = t.ses_addr
AND s.audsid = SYS_CONTEXT(‘USERENV’, ‘SESSIONID’);

SELECT used_ublk,used_urec from v$transaction;

V$TRANSACTION 列出系统中的活动事务。
USED_UBLK：使用的撤消块数
USED_UREC：使用的撤消记录数
SES_ADDR：用户会话对象地址

创建临时表
DROP TABLE my_temp_table PURGE;
CREATE GLOBAL TEMPORARY TABLE my_temp_table (
id NUMBER,
description VARCHAR2(20)
)
ON COMMIT PRESERVE ROWS;

INSERT INTO my_temp_table
WITH data AS (
SELECT 1 AS id
FROM dual
CONNECT BY level < 10000
)
SELECT rownum, TO_CHAR(rownum)
FROM data a, data b
WHERE rownum <= 1000000;


查看撤消

CREATE TABLE lh_temp_table (
id NUMBER,
description VARCHAR2(20)
);
SET AUTOTRACE ON STATISTICS;

INSERT INTO lh_temp_table
WITH data AS (
SELECT 1 AS id
FROM dual
CONNECT BY level < 10000
)
SELECT rownum, TO_CHAR(rownum)
FROM data a, data b
WHERE rownum <= 1000000;

DROP TABLE lh_temp_table PURGE;
CREATE GLOBAL TEMPORARY TABLE lh_temp_table (
id NUMBER,
description VARCHAR2(20)
)
ON COMMIT PRESERVE ROWS;
SET AUTOTRACE ON STATISTICS;

INSERT INTO lh_temp_table
WITH data AS (
SELECT 1 AS id
FROM dual
CONNECT BY level < 10000
)
SELECT rownum, TO_CHAR(rownum)
FROM data a, data b
WHERE rownum <= 1000000;

专用临时表

创建专用临时表时所使用的前缀ORA$PTT\ast \ast ONCOMMITDROPDEFINITION：在事务结束时或会话结束时删除表\ast \ast CREATEPRIVATETEMPORARYTABLEora$ptt_lh_temp_table (
id NUMBER,
description VARCHAR2(20)
)
ON COMMIT DROP DEFINITION;

INSERT INTO ora$ptt_lh_temp_table VALUES (1, ‘ONE’);

SELECT COUNT(*) FROM ora$ptt_lh_temp_table;

COMMIT;

SELECT COUNT(*) FROM ora$ptt_lh_temp_table;

ON COMMIT PRESERVE DEFINITION：在会话结束时删除
CREATE PRIVATE TEMPORARY TABLE ora$ptt_zs_temp_table (
id NUMBER,
description VARCHAR2(20)
)
ON COMMIT PRESERVE DEFINITION;

INSERT INTO ora$ptt_zs_temp_table VALUES (1, ‘ONE’);

SELECT COUNT(*) FROM ora$ptt_zs_temp_table;

select * from USER_PRIVATE_TEMP_TABLES;

提交后还是可以查看临时表的数据的
COMMIT;

断开后在连接

SELECT COUNT(*) FROM ora$ptt_zs_temp_table;