-- =======================================
-- 3. 使用示例
-- =======================================
-- ===============================
-- 测试对象
-- a. 源表
CREATE TABLE dbo.t1(
    id int IDENTITY
        PRIMARY KEY,
    col int
)
-- b. 同步的目的表
CREATE TABLE dbo.t2(
    id int IDENTITY
        PRIMARY KEY,
    col int
)
-- c. 记录操作的日志表
CREATE TABLE dbo.tb_log(
    id int IDENTITY
        PRIMARY KEY,
    user_name sysname,
    operate_type varchar(10),
    inserted XML,
    deleted xml
)
GO
 
-- a. 异步发送处理消息的触发器
CREATE TRIGGER TR_async_trigger
ON dbo.t1
FOR INSERT, UPDATE, DELETE
AS
IF @@ROWCOUNT = 0
    RETURN
 
SET NOCOUNT ON
 
-- 将要发送的数据生成xml 数据
DECLARE
    @message xml
SELECT
    @message = (
            SELECT
                table_name = (
                        SELECT TOP 1
                            OBJECT_NAME(parent_object_id)
                        FROM sys.objects
                        WHERE object_id = @@PROCID),
                trigger_name = OBJECT_NAME(@@PROCID),
                user_name = SUSER_SNAME(),
                inserted = (
                        SELECT * FROM inserted FOR XML AUTO, TYPE),
                deleted = (
                        SELECT * FROM deleted FOR XML AUTO, TYPE)
            FOR XML PATH(""), ROOT("root"), TYPE
        )
-- 发送消息
EXEC dbo.p_async_trigger_send
    @message = @message
GO
 
-- b. 处理异步触发器的存储过程
-- b.1 同步到t2 的存储过程
CREATE PROC dbo.p_Sync_t1_t2
    @message xml
AS
SET NOCOUNT ON
DECLARE
    @inserted bit,
    @deleted bit
SELECT
    @inserted = @message.exist("/root/inserted"),
    @deleted = @message.exist("/root/deleted")
IF @inserted = 1
    IF @deleted = 1 -- 更新
    BEGIN
        ;WITH
        I AS(
            SELECT
                id = T.c.value("@id[1]", "int"),
                col = T.c.value("@col[1]", "int")
            FROM @message.nodes("/root/inserted/inserted") T(c)
        ),
        D AS(
            SELECT
                id = T.c.value("@id[1]", "int"),
                col = T.c.value("@col[1]", "int")
            FROM @message.nodes("/root/deleted/deleted") T(c)
        )
        UPDATE A SET
            col = I.col
        FROM dbo.t2 A, I, D
        WHERE A.ID = I.ID
            AND I.ID = D.ID
    END
    ELSE            -- 插入
    BEGIN
        SET IDENTITY_INSERT dbo.t2 ON
        ;WITH
        I AS(
            SELECT
                id = T.c.value("@id[1]", "int"),
                col = T.c.value("@col[1]", "int")
            FROM @message.nodes("/root/inserted/inserted") T(c)
        )
        INSERT dbo.t2(
            id, col)
        SELECT
            id, col
        FROM I
        SET IDENTITY_INSERT dbo.t2 OFF
    END
ELSE                -- 删除
BEGIN
    ;WITH
    D AS(
        SELECT
            id = T.c.value("@id[1]", "int"),
            col = T.c.value("@col[1]", "int")
        FROM @message.nodes("/root/deleted/deleted") T(c)
    )
    DELETE A
    FROM dbo.t2 A, D
    WHERE A.ID = D.ID
END
GO
 
-- b.2 记录操作记录到dbo.tb_log 的存储过程
CREATE PROC dbo.p_Record_log
    @message xml
AS
SET NOCOUNT ON
DECLARE
    @inserted bit,
    @deleted bit
SELECT
    @inserted = @message.exist("/root/inserted"),
    @deleted = @message.exist("/root/deleted")
INSERT dbo.tb_log(
    user_name,
    operate_type,
    inserted,
    deleted)
SELECT
    @message.value("(/root/user_name)[1]", "sysname"),
    operate_type = CASE
                    WHEN @inserted = 1 AND @deleted = 1 THEN "update"
                    WHEN @inserted = 1 THEN "insert"
                    WHEN @deleted = 1 THEN "delete"
                END,
    @message.query("/root/inserted"),
    @message.query("/root/deleted")
GO
 
 
-- ===============================
-- 在异步触发器处理系统中登记对象
INSERT dbo.tb_async_trigger(
    table_name, trigger_name)
VALUES(
    N"t1", N"TR_async_trigger")
 
INSERT dbo.tb_async_trigger_subscriber(
    procedure_name)
SELECT N"dbo.p_Sync_t1_t2" UNION ALL
SELECT N"dbo.p_Record_log"
 
INSERT dbo.tb_async_trigger_subscribtion(
    trigger_id, procedure_id)
SELECT 1, 1 UNION ALL
SELECT 1, 2
GO

-- ===============================
-- 测试
INSERT dbo.t1
SELECT 1 UNION ALL
SELECT 2
 
UPDATE dbo.t1 SET
    col = 2
WHERE id = 1
 
DELETE dbo.t1
WHERE id = 2
 
-- 显示结果
WAITFOR DELAY "00:00:05" 
-- 延迟5 分钟, 以便有时间处理消息(因为是异步的)
SELECT * FROM dbo.t2
SELECT * FROM dbo.tb_log
GO

-- =======================================
-- 5. 删除相关的对象
-- =======================================
-- a. 删除service broker 对象
DROP SERVICE SRV_async_trigger
DROP QUEUE dbo.Q_async_trigger
DROP CONTRACT CNT_async_trigger
DROP MESSAGE TYPE MSGT_async_trigger
GO
 
-- b. 删除异步触发器处理的相关对象
DROP PROC dbo.p_async_trigger_process
DROP PROC dbo.p_async_trigger_send
DROP TABLE dbo.tb_async_trigger_subscribtion
DROP TABLE dbo.tb_async_trigger_subscriber
DROP TABLE dbo.tb_async_trigger
GO
 
-- c. 删除测试的对象
DROP TABLE dbo.tb_log, dbo.t1, dbo.t2
DROP PROC dbo.p_Sync_t1_t2, dbo.p_Record_log

USE tempdb
GO
 
-- 允许Service Broker
ALTER DATABASE tempdb SET
ENABLE_BROKER
GO

-- =======================================
-- 异步触发器对象
-- 1. service broker 对象
-- =======================================
-- a. message type, 要求使用XML 传递数据
CREATE MESSAGE TYPE MSGT_async_trigger
VALIDATION = WELL_FORMED_XML
GO
 
-- b. 只需要发送消息
CREATE CONTRACT CNT_async_trigger(
    MSGT_async_trigger SENT BY INITIATOR)
GO
 
-- c. 存储消息的队列
CREATE QUEUE dbo.Q_async_trigger
GO
 
-- d. 用于消息处理的服务
CREATE SERVICE SRV_async_trigger
    ON QUEUE dbo.Q_async_trigger(
        CNT_async_trigger)
GO
 
 
-- =======================================
-- 异步触发器对象
-- 2. 异步触发器处理的对象
-- =======================================
-- a. 登记异步触发器的表
CREATE TABLE dbo.tb_async_trigger(
    ID int IDENTITY
        PRIMARY KEY,
    table_name sysname,
    trigger_name sysname
)
 
-- b. 登记订阅异步触发器的存储过程
CREATE TABLE dbo.tb_async_trigger_subscriber(
    ID int IDENTITY
        PRIMARY KEY,
    procedure_name sysname
)
 
-- c. 异步触发器和存储过程之间的订阅关系
CREATE TABLE dbo.tb_async_trigger_subscribtion(
    trigger_id int
        REFERENCES dbo.tb_async_trigger(
            ID),
    procedure_id int
        REFERENCES dbo.tb_async_trigger_subscriber(
            ID),
    PRIMARY KEY(
        trigger_id, procedure_id)
)
GO
 
-- d. 发送消息的存储过程
CREATE PROC dbo.p_async_trigger_send
    @message xml
AS
SET NOCOUNT ON
DECLARE
    @handle uniqueidentifier
BEGIN DIALOG CONVERSATION @handle
    FROM SERVICE [SRV_async_trigger]
    TO SERVICE N"SRV_async_trigger"
    ON CONTRACT CNT_async_trigger
    WITH
        ENCRYPTION = OFF;
SEND
    ON CONVERSATION @handle
    MESSAGE TYPE MSGT_async_trigger(
        @message);
-- 消息发出即可, 不需要回复, 因此发出后即可结束会话
END CONVERSATION @handle
GO
 
-- e. 处理异步触发器发送的消息
CREATE PROC dbo.p_async_trigger_process
AS
SET NOCOUNT ON
DECLARE
    @handle uniqueidentifier,
    @message xml,
    @rows int
SET @rows = 1
WHILE @rows > 0
BEGIN
    -- 处理已经收到的消息
    WAITFOR(
        RECEIVE TOP(1)
            @handle = conversation_handle,
            @message = CASE
                            WHEN message_type_name = N"MSGT_async_trigger"
                                THEN CONVERT(xml, message_body)
                            ELSE NULL
                        END
        FROM dbo.Q_async_trigger
    ), TIMEOUT 10
    SET @rows = @@ROWCOUNT
    IF @rows > 0
    BEGIN
        -- 结束会话
        END CONVERSATION @handle;
 
        -- 处理消息
        -- a. 取发送者信息
        DECLARE
            @table_name sysname,
            @trigger_name sysname,
            @sql nvarchar(max)
        SELECT
            @table_name = @message.value("(/root/table_name)[1]", "sysname"),
            @trigger_name = @message.value("(/root/trigger_name)[1]", "sysname")
 
        -- b. 调用异步触发器订阅的存储过程
        ;WITH
        SUB AS(
            SELECT
                TR.table_name,
                TR.trigger_name,
                SUB.procedure_name
            FROM dbo.tb_async_trigger TR,
                dbo.tb_async_trigger_subscriber SUB,
                dbo.tb_async_trigger_subscribtion TRSUB
            WHERE TRSUB.trigger_id = TR.ID
                AND TRSUB.procedure_id = SUB.ID
        )
        SELECT
            @sql = (
                    SELECT
                        N"
EXEC " + procedure_name + N"
    @message
"
                    FROM SUB
                    WHERE table_name = @table_name
                        AND trigger_name = @trigger_name
                    FOR XML PATH(""), ROOT("r"), TYPE
                ).value("(/r)[1]", "nvarchar(max)")
        EXEC sp_executesql @sql, N"@message xml", @message
    END
END
GO
 
-- f. 绑定处理的存储过程到队列
ALTER QUEUE dbo.Q_async_trigger
    WITH ACTIVATION(
        STATUS = ON,
        PROCEDURE_NAME = dbo.p_async_trigger_process,
        MAX_QUEUE_READERS = 10,
        EXECUTE AS OWNER)
GO