A SQL Server trigger is a piece of procedural code. It is just like a stored procedure which is only executed when a given event happens. There are different types of events that can fire a trigger. To name you a few, the insertion of rows in a table, a change in a table structure...
Triggers in SQL Server - Learn about SQL Server triggers, their purpose, types, and benefits. Understand DML and DDL triggers with practical use cases.
In this Guide Before showing how to use triggers in SQL Server, the first sections of this guide describe some basic database concepts that are needed to explain triggers: Primary and foreign keys are described, and an example database schema is introduced to show how they can create associa...
Trigger names exist in the schema namespace, meaning that all triggers must have unique names within a schema. Triggers in different schemas can have the same name. It is possible to define multiple triggers for a given table that have the same trigger event and action time. For example, ...
In this example, after each update on ‘SALARY’ column ofemployee_salarywith hike greater than 50000, it will fire a ‘after update’ trigger and insert the new updated data into aemployee_salary_logtable. 2.1 Create tables and trigger. ...
触发器的意思就是当我们对数据库对象(一般是表或视图)进行insert、update、delete操作的时候,这些操作会相应的触发一些事件的执行,通常要执行的事件被写成PL/SQL程序,那么这些数据库对象上的事件相关的程序就是触发器(trigger)。Oracle数据库中,触发器分为before、after、instead of三种,其中before、after主要对于表操作...
It is possible to define multiple triggers for a given table that have the same trigger event and action time. For example, you can have twoBEFORE UPDATEtriggers for a table. By default, triggers that have the same trigger event and action time activate in the order they were created. ...
The SELECT privilege on any table or view that is referenced in the search-condition of the triggered-action The privileges that are required to execute the statements in SQL-trigger-body If the SECURED option is specified, either SECADM authority or the CREATE_SECURE_OBJECT privilege is needed....
For example: REFERENCING OLD_TABLE AS DeletedHotels allows you to use that new identifier (DeletedHotels) in the triggered-SQL-statement: DELETE FROM HotelAvailability WHERE hotel_id IN (SELECT hotel_id FROM DeletedHotels) The old and new transition tables map to ajava.sql.ResultSetwith cardinal...
The PL/SQL block or CALL subprogram that the database runs to fire the trigger. A CALL subprogram is either a PL/SQL subprogram or a Java subprogram in a PL/SQL wrapper. If trigger_body is a PL/SQL block and it contains errors, then the CREATE [OR REPLACE] statement fails. Restrictio...