例如在窗口sql*plus 1 中修改emp 的数据 updateempsetsal=sal+100whereeno='123'; 虽然sql*plus 1 窗口已经提示更新, 但是事务没有提交! 此时再打开另一个窗口sql*plus2 , 同样也执行修改, 执行上述同样的语句, 不是提示已更新, 而是一直等待. 这是因为sql*plus 1 封锁了记录, 但是事务没有结束, 锁不会...
Note that NEW is null in DELETEtriggers, so returning that is usually not sensible. The usual idiom in DELETE triggers is to return OLD.INSTEAD OF triggers (which are always row-level triggers, and may only be used on views) can return null to signal that they did not perform any up...
没有行号的情况 设定行号 1、选中Tools 2、Editor 设定[Display Line numbers] 3、Window Types –>Sql Window 选中显示行号 4、点击确认后,行号显示出来了 5、修改行号字体大小... PL/SQL Developer 使用技巧之【快捷输入】设置方法 PL/SQL Developer设置快捷输入常用SQL字段: 针对一些常用的SQL字段,比如:select...
1、触发器说明 触发器是一种在事件发生时隐式地自动执行的PL/SQL块,不能接受参数,不能被显式调用 2、触发器类型 根据触发器所创建的语句及所影响的对象的不同,将触发器分为以下3类 (1)DML触发器 对数据表进行DML语句操作(如insert、update、delete)时所触发的触发器,可以分为: 语句级触发器或行级触发器:...
PL/SQL Triggers - Learn about PL/SQL triggers, their types, and how to use them effectively in your database applications.
Free Data Engineering & SQL tips! Get daily tips to your inbox on real-world use cases Be the first to know the latest interview questions Get free PDFs right away to know the key points Type your email… Yes, give me your free tips >> One response PL/SQL- Expected Errors in Exe...
触发器也是一种带名的PL/SQL块。触发器类似于过程和函数,因为它们都是拥有声明、执行和异常处理过程的带名PL/SQL块。与包类似,触发器必须存储在数据库中并且不能被块进行本地化声明。 对于触发器而言,当触发事件发生的时候就会显式地执行该触发器,并且触发器不接受参数。
9 PL/SQL Triggers 10 PL/SQL Packages 11 PL/SQL Error Handling 12 PL/SQL Optimization and Tuning 13 PL/SQL Language Elements 14 SQL Statements for Stored PL/SQL Units A PL/SQL Source Text Wrapping B PL/SQL Name Resolution C PL/SQL Program Limits D PL/SQL Reserved Words and Keywords E...
Once you have created a trigger in Oracle, you might find that you need to remove it from the database. You can do this with the DROP TRIGGER statement.Syntax The syntax to a drop a trigger in Oracle in Oracle/PLSQL is: DROP TRIGGER trigger_name; Parameters or Arguments trigger_name ...
The syntax to create aBEFORE UPDATE Triggerin Oracle/PLSQL is: CREATE [ OR REPLACE ] TRIGGERtrigger_nameBEFORE UPDATE ONtable_name[ FOR EACH ROW ] DECLARE -- variable declarations BEGIN -- trigger code EXCEPTION WHEN ... -- exception handling END; ...