数据库5-数据库完整性剖析.ppt

示例 CREATE TRIGGER reminder ON EMP FOR DELETE AS Print You have just deleted + Cast(@@rowcount as varchar) + record(s)! Create Trigger CREATE TRIGGER trigger_name ON { table | view ) { { { FOR | AFTER | INSTEAD OF } { [ INSERT ][， ][DELETE ][， ][ UPDATE ] } AS Sql_Statement [ ．．．n ] } Inserted 和Deleted 虚表 在触发器执行期间，SQL Server维护了两个临时的虚表: Deleted 和 Inserted. These tables contain all the records inserted or deleted during the operation that fired the trigger. New row 200212123 3 68 INSERT操作工作过程 SC SNO CNO Grade ------ ---------- -------200215121 1 85 200215121 2 69 200215122 1 92 200212123 2 77 “…insert a new row into SC table…” 200212123 3 68 200212123 3 68 SNO CNO Grade INSERTED DELETE 操作工作过程 “…delete a row from SC table…” SC SNO CNO Grade ------ ---------- -------200215121 1 85 200215121 2 69 200215122 1 92 200212123 2 77 … SC SNO CNO Grade ------ ---------- -------200215121 1 85 200215121 2 69 200215122 1 92 200212123 3 68 SNO CNO Grade DELETED Update操作工作过程 SC SNO CNO Grade ------ ---------- -------200215121 1 85 200215121 2 69 200215122 1 92 200212123 2 77 200212123 3 68 200212123 3 68 SNO CNO Grade DELETED 200212123 3 75 SNO CNO Grade INSERTED 20021