首先,确保你已经创建了需要的触发器。触发器可以在表上的特定事件(例如INSERT、UPDATE、DELETE)发生时执行一些操作。 执行一个更新操作,以触发触发器的执行。可以使用UPDATE语句来更新表中的任意一行,即使不实际更改任何数据。 例如,假设有一个名为users的表,其中包含一个名为trigger_example的触发器。你可以执行以...
RangeVar *relation;/* relation to update */List *targetList;/* the target list (of ResTarget) */// 对应语句中的set id = 0;信息在这里Node *whereClause;/* qualifications */List *fromClause;/* optional from clause for more tables */List *returningList;/* list of expressions to return ...
postgres=# update pg_attribute set attnum = 2 where attrelid = 24894 and attname = 'vname'; UPDATE 1 postgres=# update pg_attribute set attnum = 1 where attrelid = 24894 and attname = 'id'; UPDATE 1 postgres=# select ctid,* from tbl_kenyon; ctid | id | vname | remark ---...
要评估一个用户是否在权限上持有赋权选项,给权限键字附加 WITH GRANT OPTION;比如 'UPDATE WITH GRANT OPTION'。 3. 模式可视性查询函数: 那些判断一个对象是否在当前模式搜索路径中可见的函数。 如果一个表所在的模式在搜索路径中,并且没有同名的表出现在搜索路径的更早的地方,那么就说这个表视可见的。 它等效...
select * from t1; 包含一个INSERT/UPDATE/DELETE查询,且带RETURNING条件。...根据传入的第二个参数allowDup,如果第一步查找到,从哈希表中决定是否删除。...1.2.3 PortalDefineQuery 定义portal数据,包含了:查询语句sourceText、PlannedStmts、查询完成标记qc。.../后退 可以从holdStore中获取,也可以从Exect...
(update parttbl set a = a returning parttbl.*) + update parttbl set a = u.a from u; + <waiting ...> +step c1: COMMIT; +step complexpartupdate: <... completed> +error in steps c1 complexpartupdate: ERROR: unexpected table_lock_tuple status: 1 +step c2: COMMIT; diff --git a...
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When an update moves a row between partitions (supported since 2f17844), our normal logic for following update chains in READ COMMITTED mode doesn't work anymore. Cross partition updates are modeled as an delete from the old and insert into the new partition. No ctid chain exists across part...
ctid which are all described inSystem Columns. ThePostgreSQL docs on inheritancehave examples of using it, but we thought it worthwile to repeat the exercise since it's not that common knowledge and is unique enough feature of PostgreSQL that others coming from other relational databases, may ...
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