DML触发器是SQL Server数据库中应用最广泛的触发器，在维护数据完整性、提高数据安全性、满足复杂的数据约束等方面具有重要作用。文中对DML触发器的应用进行详细研究。首先，介绍了DML触发器包含的AFTER和IN-STEAD OF两种类型；其次，通过图形表示了AFTER触发器的触发顺序，并阐明了指定触发顺序需要注意的问题；然后，研究INSERT、DELETE、UPDATE三类触发器的工作原理；最后，给出了DML触发器的几个应用技巧。实际运用时要结合文中的研究内容进行详细设计，以便提高数据库系统的整体性能。%DML trigger is the trigger that most widely used in SQL Server database,and plays an important role in maintaining data integ-rity,improving data security,and meeting complex data constraints. Study the application of DML trigger in detail. First,introduce the two types of AFTER and INSTEAD OF that included in DML trigger;Second,show the trigger sequence of AFTER trigger through a graph-ical,and clarify the needing attention problems of specified trigger;Then research the working principle of the three class triggers of IN-SERT,DELETE and UPDATE;Finally,give several application skills of DML trigger. The practical application does the detail design should combine this contents in order to improve the overall performance of database system.
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