2.使用触发器自动更新 update_at 字段:可以创建一个触发器(Trigger),在更新记录时自动将 update_at 字段设置为当前时间。首先,创建一个触发器函数:CREATE OR REPLACE FUNCTION update_timestamp() RETURNS TRIGGER AS $$ BEGIN NEW.update_at = CURRENT_TIMESTAMP; RETURN NEW; END; $$ LANGUAGE plpgsql;然后,...
[maxvalue n]:序列的最大值,缺省值是9999999999999999999999999999。 [increment by n]:序列递增的步长,缺省值是1。 [start with n]:序列的起始值,缺省值是minvalue,如果n小于minvalue,创建序列会报语法错误。 [cache n|nocache]:是否采用缓存机制,nocache不采用缓存,缺省cache 20,数据库每次会生成20个值放在缓...
create sequence tbProd_seq minvalue 1 maxvalue 9999999 start with 1 increment by 1 cache 100; insert into tbprod values(tbProd_seq.Nextval,'电视机','创维','48英寸等离子电视机'); insert into tbprod values(tbProd_seq.Nextval,'电视机','创维','56英寸数字电视机'); insert into tbprod val...
[ FOR UPDATE [ OF table_name [, ...] ] ] SET 修改运行时参数。 SET [ SESSION | LOCAL ] name { TO | = } { value | 'value' | DEFAULT } SET [ SESSION | LOCAL ] TIME ZONE { time_zone | LOCAL | DEFAULT } SET CONSTRAINTS 设置当前事务的约束检查模式。 SET CONSTRAINTS { ALL | ...
GRANT { { SELECT | INSERT | UPDATE | DELETE | RULE | REFERENCES | TRIGGER } [,...] | ALL [ PRIVILEGES ] } ON [ TABLE ] table_name [, ...] TO { username | GROUP group_name | PUBLIC } [, ...] [ WITH GRANT OPTION ] GRANT { { CREATE | TEMPORARY | TEMP } [,...] |...
UPDATE 1 postgres=# select * from tbl2; id | info ---+--- 2 | test (1 row) 【强制】对于频繁更新的表,建议建表时指定表的fillfactor=85,每页预留15%的空间给HOT更新使用。 1 2 postgres=# create table test123(id int, info text) with(fillfactor=85); CREATE TABLE 【强制】...
SELECT FOR UPDATE NOWAIT ✔️ ✔️ 关联删除 DELETE JOIN DELETE USING 数据合并(MERGE) ❌ ✔️ 数据合并(专用语句) INSERT ON DUPLICATE、REPLACE INSERT ON CONFLICT DML 语句中的 RETURNING 子句 ❌ ✔️ DML 语句中的 CTE ✔️ ✔️ CTE 中的 DML 语句 ❌ ✔️ DML 操作...
Insert row operation requires to provide explicit value for Primary Key column, even though default/autoincrement value is defined. Usage of the Order By parameter is recommended for Get rows action in order to get deterministic results in the output. If Order By isn't specified, the rows ...
mysql> CREATE TABLE test (-> id INT UNSIGNED NOT NULL AUTO_INCREMENT,-> data VARCHAR(64) DEFAULT NULL,-> ts TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,-> PRIMARY KEY (id)-> );Query OK, 0 rows affected (0.02 sec)mysql> REPLACE INTO test VALUES (1, '...
(id)on delete restrict on update restrict;';EXECUTE strSQL;---指定序列strSQL :='create sequence t_self_evaluation_'||currsnum||'_id_seq increment by 1minvalue 1 maxvalue 9223372036854775807 start with 1owned by t_self_evaluation_'||currsnum||'.id';EXECUTE strSQL;rownum := rownum +...