Triggers in SQL Server - Learn about SQL Server triggers, their purpose, types, and benefits. Understand DML and DDL triggers with practical use cases.
Basic State Machine with Triggers and Guards(带触发器和保护的基本状态机) 起始状态机模式从它所展示的重要状态的角度来描述一个实体(例如类、参与者、用例或测试用例)。状态机图表明实体可以处于两种状态之一,并且它在两种状态之间转换。转换已经用触发和保护进行了注释,指示了启动(触发)状态改变的是什么,以及转换...
PL/SQL Triggers - Learn about PL/SQL triggers, their types, and how to use them effectively in your database applications.
T-SQL DDL Trigger A special type of T-SQL stored procedure that executes one or more T-SQL statements in response to database-scoped or server-scoped events. For example, a DDL trigger may fire if a table is altered or dropped using ALTER or DROP TABLE. CLR DDL Trigger A CLR trigger...
Note:The INSERTED record can be used in the insert and update SQL triggers. With IF statements, we’ve tested values and SET values if they were not set before At the end of the query, we performed the INSERT statement (the one replacing the original one that fired this trigger) ...
For example, if we specify an instead of trigger for delete on a table, when delete statement is issued against the table, the instead of trigger is fired and the T-SQL block inside the triggers in SQL Server is executed but the actual delete does not happen. ...
The first trigger in the query above is HumanResources.dEmployee. Let’s use that trigger as the example in the remainder of this tip. Note – The key column in thesys.triggersview in this context is the is_disabled column. Disabling a trigger with theDISABLE TRIGGERcommand ...
For example, the basic syntax for creating a trigger that runs after a DELETE operation on a table is as follows: 1 2 3 4 5 6 7 CREATE TRIGGER AfterTriggerName ON TableName AFTER DELETE AS BEGIN /* Series SQL code statements */ END; This guide shows how to work with triggers in...
CREATE TRIGGER trigger_name ON { DATABASE | ALL SERVER} [WITH ddl_trigger_option] FOR { event_type | event_group } AS {sql_statement}In the above syntax: trigger_name is the name of the new trigger being created. ON DATABASE specifies that the trigger is fired for DATABASE or ALL ...
Example 2. A PL/pgSQL Trigger Procedure For Auditing This example trigger ensures that any insert, update or delete of a row in the emp table is recorded (i.e., audited) in the emp_audit table. The current time and user name are stamped into the row, together with the type of opera...