SQL Server 触发器实例详解

create trigger tgr_nameon table_namewith encrypion –加密触发器 for update...as Transact-SQL

--创建insert插入类型触发器if (object_id('tgr_classes_insert', 'tr') is not null) drop trigger tgr_classes_insertgocreate trigger tgr_classes_inserton classes for insert --插入触发as --定义变量 declare @id int, @name varchar(20), @temp int; --在inserted表中查询已经插入记录信息 select @id = id, @name = name from inserted; set @name = @name + convert(varchar, @id); set @temp = @id / 2; insert into student values(@name, 18 + @id, @temp, @id); print '添加学生成功！';go--插入数据insert into classes values('5班', getDate());--查询数据select * from classes;select * from student order by id; 

--delete删除类型触发器if (object_id('tgr_classes_delete', 'TR') is not null) drop trigger tgr_classes_deletegocreate trigger tgr_classes_deleteon classes for delete --删除触发as print '备份数据中……'; if (object_id('classesBackup', 'U') is not null) --存在classesBackup，直接插入数据 insert into classesBackup select name, createDate from deleted; else --不存在classesBackup创建再插入 select * into classesBackup from deleted; print '备份数据成功！';go----不显示影响行数--set nocount on;delete classes where name = '5班';--查询数据select * from classes;select * from classesBackup; 

--update更新类型触发器if (object_id('tgr_classes_update', 'TR') is not null) drop trigger tgr_classes_updategocreate trigger tgr_classes_updateon classes for updateas declare @oldName varchar(20), @newName varchar(20); --更新前的数据 select @oldName = name from deleted; if (exists (select * from student where name like '%'+ @oldName + '%')) begin --更新后的数据 select @newName = name from inserted; update student set name = replace(name, @oldName, @newName) where name like '%'+ @oldName + '%'; print '级联修改数据成功！'; end else print '无需修改student表！';go--查询数据select * from student order by id;select * from classes;update classes set name = '五班' where name = '5班'; 

if (object_id('tgr_classes_update_column', 'TR') is not null) drop trigger tgr_classes_update_columngocreate trigger tgr_classes_update_columnon classes for updateas --列级触发器：是否更新了班级创建时间 if (update(createDate)) begin raisError('系统提示：班级创建时间不能修改！', 16, 11); rollback tran; endgo--测试select * from student order by id;select * from classes;update classes set createDate = getDate() where id = 3;update classes set name = '四班' where id = 7; 

create trigger tgr_nameon table_namewith encryption instead of update...as T-SQL 

if (object_id('tgr_classes_inteadOf', 'TR') is not null) drop trigger tgr_classes_inteadOfgocreate trigger tgr_classes_inteadOfon classes instead of delete/*, update, insert*/as declare @id int, @name varchar(20); --查询被删除的信息，病赋值 select @id = id, @name = name from deleted; print 'id: ' + convert(varchar, @id) + ', name: ' + @name; --先删除student的信息 delete student where cid = @id; --再删除classes的信息 delete classes where id = @id; print '删除[ id: ' + convert(varchar, @id) + ', name: ' + @name + ' ] 的信息成功！';go--testselect * from student order by id;select * from classes;delete classes where id = 7; 

if (object_id('tgr_message', 'TR') is not null) drop trigger tgr_messagegocreate trigger tgr_messageon student after insert, updateas raisError('tgr_message触发器被触发', 16, 10);go--testinsert into student values('lily', 22, 1, 7);update student set sex = 0 where name = 'lucy';select * from student order by id;

alter trigger tgr_messageon studentafter deleteas raisError('tgr_message触发器被触发', 16, 10);go--testdelete from student where name = 'lucy';

--禁用触发器disable trigger tgr_message on student;--启用触发器enable trigger tgr_message on student;

--查询已存在的触发器select * from sys.triggers;select * from sys.objects where type = 'TR';--查看触发器触发事件select te.* from sys.trigger_events te join sys.triggers ton t.object_id = te.object_idwhere t.parent_class = 0 and t.name = 'tgr_valid_data';--查看创建触发器语句exec sp_helptext 'tgr_message'; 

if ((object_id('tgr_valid_data', 'TR') is not null)) drop trigger tgr_valid_datagocreate trigger tgr_valid_dataon studentafter insertas declare @age int, @name varchar(20); select @name = s.name, @age = s.age from inserted s; if (@age < 18) begin raisError('插入新数据的age有问题', 16, 1); rollback tran; endgo--testinsert into student values('forest', 2, 0, 7);insert into student values('forest', 22, 0, 7);select * from student order by id;

if (object_id('log', 'U') is not null) drop table loggocreate table log( id int identity(1, 1) primary key, action varchar(20), createDate datetime default getDate())goif (exists (select * from sys.objects where name = 'tgr_student_log')) drop trigger tgr_student_loggocreate trigger tgr_student_logon studentafter insert, update, deleteas if ((exists (select 1 from inserted)) and (exists (select 1 from deleted))) begin insert into log(action) values('updated'); end else if (exists (select 1 from inserted) and not exists (select 1 from deleted)) begin insert into log(action) values('inserted'); end else if (not exists (select 1 from inserted) and exists (select 1 from deleted)) begin insert into log(action) values('deleted'); endgo--testinsert into student values('king', 22, 1, 7);update student set sex = 0 where name = 'king';delete student where name = 'king';select * from log;select * from student order by id;