1、https://www.cnblogs.com/cxeye/p/4106030.html觸發器

2、

1.插入操作（Insert）
Inserted表有資料，Deleted表無資料

2.刪除操作（Delete）
Inserted表無資料，Deleted表有資料

3.更新操作（Update）
Inserted表有資料（新資料），Deleted表有資料（舊資料）

Use TestDB
Declare @tranError int -- 定義變數
Set @tranError=0     
 BEGIN TRAN; 
        Insert Into Person(PersonId,PersonName) Values('1','zhang');
        Set @tranError = @tranError + @@Error;
        Insert Into Person(PersonId,PersonName) Values('1','wang');
        Set @tranError = @tranError + @@Error;
        Insert Into Person(PersonId,PersonName) Values('3','sun');
        Set @tranError = @tranError + @@Error;
    If @tranError = 0
        Commit Tran
    Else
        Rollback Tran
/*
    自定義一個變數來判斷最後是否發生過錯誤。
*/

Use TestDB
Begin Try
    Begin Transaction
        Insert Into Person(PersonId,PersonName) Values('1','zhang')
        Insert Into Person(PersonId,PersonName) Values('1','wang')
        Insert Into Person(PersonId,PersonName) Values('3','sun')
    Commit Transaction
End Try
Begin Catch
    Rollback
 
 Transation
End Catch
/*
    使用TryCatch來捕獲異常。
    如果 TRY 塊內生成的錯誤導致當前事務的狀態失效，
    則將該事務歸類為不可提交的事務。
    如果通常在 TRY 塊外中止事務的錯誤在 TRY 內發生時，
    就會導致事務進入不可提交狀態。
    不可提交的事務只能執行讀操作或 ROLLBACK TRANSACTION。
    該事務不能執行任何可能生成寫操作或 COMMIT TRANSACTION 的 Transact-SQL 語句。
    如果事務被分類為不可提交的事務，則 XACT_STATE 函式會返回值 -1。
*/

 語法

create trigger tgr_name
on table_name
with encrypion –加密觸發器
    for update...
as
    Transact-SQL

    # 建立insert型別觸發器

--建立insert插入型別觸發器
if (object_id('tgr_classes_insert', 'tr') is not null)
    drop trigger tgr_classes_insert
go
create trigger tgr_classes_insert
on classes
    for insert --插入觸發
as
    --定義變數
    declare @id int, @name varchar(20), @temp int;
    --在inserted表中查詢已經插入記錄資訊
    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 '新增學生成功！';
go
--插入資料
insert into classes values('5班', getDate());
--查詢資料
select * from classes;
select * from student order by id;
     insert觸發器，會在inserted表中新增一條剛插入的記錄。

 

    # 建立delete型別觸發器

--delete刪除型別觸發器
if (object_id('tgr_classes_delete', 'TR') is not null)
    drop trigger tgr_classes_delete
go
create trigger tgr_classes_delete
on classes
    for delete --刪除觸發
as
    print '備份資料中……';    
    if (object_id('classesBackup', 'U') is not null)
        --存在classesBackup，直接插入資料
        insert into classesBackup select name, createDate from deleted;
    else
        --不存在classesBackup建立再插入
        select * into classesBackup from deleted;
    print '備份資料成功！';
go
--
--不顯示影響行數
--set nocount on;
delete classes where name = '5班';
--查詢資料
select * from classes;
select * from classesBackup;
   delete觸發器會在刪除資料的時候，將剛才刪除的資料儲存在deleted表中。

 

    # 建立update型別觸發器

--update更新型別觸發器
if (object_id('tgr_classes_update', 'TR') is not null)
    drop trigger tgr_classes_update
go
create trigger tgr_classes_update
on classes
    for update
as
    declare @oldName varchar(20), @newName varchar(20);
    --更新前的資料
    select @oldName = name from deleted;
    if (exists (select * from student where name like '%'+ @oldName + '%'))
        begin
            --更新後的資料
            select @newName = name from inserted;
            update student set name = replace(name, @oldName, @newName) where name like '%'+ @oldName + '%';
            print '級聯修改資料成功！';
        end
    else
        print '無需修改student表！';
go
--查詢資料
select * from student order by id;
select * from classes;
update classes set name = '五班' where name = '5班';
     update觸發器會在更新資料後，將更新前的資料儲存在deleted表中，更新後的資料儲存在inserted表中。

 

    # update更新列級觸發器

if (object_id('tgr_classes_update_column', 'TR') is not null)
    drop trigger tgr_classes_update_column
go
create trigger tgr_classes_update_column
on classes
    for update
as
    --列級觸發器：是否更新了班級建立時間
    if (update(createDate))
    begin
        raisError('系統提示：班級建立時間不能修改！', 16, 11);
        rollback tran;
    end
go
--測試
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;
     更新列級觸發器可以用update是否判斷更新列記錄；

 

    # instead of型別觸發器

       instead of觸發器表示並不執行其定義的操作（insert、update、delete）而僅是執行觸發器本身的內容。

       建立語法

create trigger tgr_name
on table_name
with encryption
    instead of update...
as
    T-SQL
   

      # 建立instead of觸發器

if (object_id('tgr_classes_inteadOf', 'TR') is not null)
    drop trigger tgr_classes_inteadOf
go
create trigger tgr_classes_inteadOf
on classes
    instead of delete/*, update, insert*/
as
    declare @id int, @name varchar(20);
    --查詢被刪除的資訊，病賦值
    select @id = id, @name = name from deleted;
    print 'id: ' + convert(varchar, @id) + ', name: ' + @name;
    --先刪除student的資訊
    delete student where cid = @id;
    --再刪除classes的資訊
    delete classes where id = @id;
    print '刪除[ id: ' + convert(varchar, @id) + ', name: ' + @name + ' ] 的資訊成功！';
go
--test
select * from student order by id;
select * from classes;
delete classes where id = 7;
   

      # 顯示自定義訊息raiserror

if (object_id('tgr_message', 'TR') is not null)
    drop trigger tgr_message
go
create trigger tgr_message
on student
    after insert, update
as raisError('tgr_message觸發器被觸發', 16, 10);
go
--test
insert into student values('lily', 22, 1, 7);
update student set sex = 0 where name = 'lucy';
select * from student order by id;

    # 修改觸發器

alter trigger tgr_message
on student
after delete
as raisError('tgr_message觸發器被觸發', 16, 10);
go
--test
delete from student where name = 'lucy';

    # 啟用、禁用觸發器

--禁用觸發器
disable trigger tgr_message on student;
--啟用觸發器
enable trigger tgr_message on student;

    # 查詢建立的觸發器資訊

--查詢已存在的觸發器
select * from sys.triggers;
select * from sys.objects where type = 'TR';

--檢視觸發器觸發事件
select te.* from sys.trigger_events te join sys.triggers t
on t.object_id = te.object_id
where t.parent_class = 0 and t.name = 'tgr_valid_data';

--檢視建立觸發器語句
exec sp_helptext 'tgr_message';

    # 示例，驗證插入資料

if ((object_id('tgr_valid_data', 'TR') is not null))
    drop trigger tgr_valid_data
go
create trigger tgr_valid_data
on student
after insert
as
    declare @age int,
            @name varchar(20);
    select @name = s.name, @age = s.age from inserted s;
    if (@age < 18)
    begin
        raisError('插入新資料的age有問題', 16, 1);
        rollback tran;
    end
go
--test
insert into student values('forest', 2, 0, 7);
insert into student values('forest', 22, 0, 7);
select * from student order by id;

    # 示例，操作日誌

if (object_id('log', 'U') is not null)
    drop table log
go
create table log(
    id int identity(1, 1) primary key,
    action varchar(20),
    createDate datetime default getDate()
)
go
if (exists (select * from sys.objects where name = 'tgr_student_log'))
    drop trigger tgr_student_log
go
create trigger tgr_student_log
on student
after insert, update, delete
as
    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');
    end
go
--test
insert 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;