Using change tracking on a table that has his records constantly deleted and re-inserted

问题

I'm building a layer over an application that needs to catch the changes happens to the data and update another system with these changes (SIF) and I faced a problem with a specific table, the application truncates the table, and insert a new set of records every time the data reconciled. In order to solve this problem, I used a shadow table and Merged the records from the original table, and as I found that I might use the same method with other tables in the future, I created a generic SP that reads the structure of the tow tables and constructs a merge statement then runs it and I'm sharing the SP in the first answer, hope someone makes use of it, any comment or question is welcomed. The SP works as long as the two tables are identical and the change tracking is working beautifully.

回答1:

1- Creating the SP

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO

CREATE Procedure [Compare2Tables](
    @DestSchema as NVarchar(255) ,
    @DestTable as NVarchar(255),
    @SrcSchema as NVARCHAR(255) ,
    @srcTable as NVARCHAR(255) ,
    @AdditionalCondition as NVARCHAR(MAX) 
    )
AS
BEGIN
DECLARE @JoiningFields as NVARCHAR(MAX)
DECLARE @MismatchingCondition as NVARCHAR(MAX)
DECLARE @UpdateOtherFields as NVARCHAR(MAX)
DECLARE @InsertDestFields as NVARCHAR(MAX)
DECLARE @InsertSrcFilds as NVARCHAR(MAX)
DECLARE @TheSQL as NVARCHAR(MAX)
DECLARE @CurrentColumn as NVARCHAR(255)
DECLARE @CurrentConstraint as NVARCHAR(255)
DECLARE @tablespecs TABLE (
TABLE_SCHEMA nvarchar(255) ,
TABLE_NAME  nvarchar(255) ,
COLUMN_NAME nvarchar(255) ,
CONSTRAINT_NAME nvarchar(255) 
)

insert into @tablespecs SELECT DISTINCT T.TABLE_SCHEMA , T.TABLE_NAME , T.COLUMN_NAME ,CONSTRAINT_NAME 
FROM INFORMATION_SCHEMA.COLUMNS t
LEFT JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE K ON T.TABLE_NAME = K.TABLE_NAME AND T.TABLE_SCHEMA = K.TABLE_SCHEMA AND T.COLUMN_NAME = K.COLUMN_NAME
WHERE T.TABLE_NAME = @DestTable
AND T.TABLE_SCHEMA = @DestSchema

set @JoiningFields = '  '
set @MismatchingCondition = '  '
set @UpdateOtherFields  = ' '
set @InsertDestFields = ' '
set @InsertSrcFilds = ' '

while exists (select * from @tablespecs) 
    Begin
        set @CurrentColumn = (Select top 1 Column_name from @tablespecs)
        --select @CurrentColumn
        Set @CurrentConstraint = (Select CONSTRAINT_NAME FROM @tablespecs WHERE COLUMN_NAME = @CurrentColumn)
        if not @CurrentConstraint is null 
            set @JoiningFields = @JoiningFields + ' D.' + @CurrentColumn + '=S.' + @CurrentColumn + ' AND '
        ELSE
            begin
            SET @MismatchingCondition = @MismatchingCondition + ' ISNULL(D.' + @CurrentColumn + ',0) <> ISNULL(S.' + @CurrentColumn + ',0) OR '
            SET @updateOtherFields = @updateOtherFields + 'D.' +@CurrentColumn  + ' = S.' + @CurrentColumn + ','
            end
            set @InsertDestFields = @InsertDestFields + @CurrentColumn + ','
            set @InsertSrcFilds = @InsertSrcFilds + 'S.' + @CurrentColumn + ',';

        delete from @tablespecs where Column_Name = @CurrentColumn
    End
    SET @JoiningFields = SUBSTRING(@JoiningFields , 1 , len(@JoiningFields) - 4)
    SET @MismatchingCondition = SUBSTRING(@MismatchingCondition , 1 , len(@MismatchingCondition) - 3)
    SET @UpdateOtherFields = SUBSTRING(@UpdateOtherFields , 1 , len(@updateOtherFields) - 1)
    SET @InsertDestFields = SUBSTRING(@InsertDestFields , 1 , len(@InsertDestFields) - 1)
    SET @InsertSrcFilds = SUBSTRING(@InsertSrcFilds , 1 , len(@InsertSrcFilds) - 1)

--select @JoiningFields JoiningFields , @UpdateOtherFields UpdateOtherFields , @MismatchingCondition MismatchingCondition , @InsertDestFields InsertDestFields , @InsertSrcFilds InsertSrcFilds

set @TheSQL = 'MERGE INTO ' + @DestSchema + '.' + @DestTable + ' AS D using (SELECT * FROM ' + @SrcSchema+'.'+ @SrcTable + ' ' + @AdditionalCondition + ') AS S ON ' + @JoiningFields + ' WHEN MATCHED AND (' + @MismatchingCondition + ') 
THEN UPDATE SET ' + @updateOtherFields + ' 
WHEN NOT MATCHED BY TARGET THEN
INSERT (' + @InsertDestFields + ') 
VALUES (' + @InsertSrcFilds + ')
WHEN NOT MATCHED BY SOURCE THEN
DELETE;'

EXECUTE sp_executesql @TheSQL

END

2- Now see the implementation

--Create theSource table
CREATE TABLE TheSource
(
TheID INT PRIMARY KEY,
TheName VARCHAR(100),
TheCost MONEY,
ProductionYear VARCHAR(4)
) 
GO

--Fill some records in TheSource
INSERT INTO TheSource
VALUES
(1, 'Word', 10.00,'2018'),
(2, 'Access', 20.00,'2018'),
(3, 'Excel', 30.00,'2017'),
(4, 'PowerPoint', 40.00,'2017')
GO

--Create Destination table
CREATE TABLE TheDest
(
TheID INT PRIMARY KEY,
TheName VARCHAR(100),
TheCost MONEY,
ProductionYear VARCHAR(4)
) 
GO
--The Dest table is left with no records on purpose
SELECT * FROM TheSource
SELECT * FROM TheDest
GO

--The folloing syntax will fill only products of 2017
execute [Compare2Tables]   'dbo','TheDest','dbo', 'TheSource','Where ProductionYear = 2017'
SELECT * FROM TheDest

-- Syncronizing all records regardless of the year
execute [Compare2Tables]   'dbo','TheDest','dbo', 'TheSource',' '
SELECT * FROM TheDest

--Updating one row in the source, then sync
update TheSource set TheCost = 33.00 where TheName = 'Access'
execute [Compare2Tables]   'dbo','TheDest','dbo', 'TheSource',' '
SELECT * FROM TheDest

-- updating all records in the source, then sync
update TheSource set TheCost = TheCost * 0.75
execute [Compare2Tables]   'dbo','TheDest','dbo', 'TheSource',' '
SELECT * FROM TheDest

来源：https://stackoverflow.com/questions/53148097/using-change-tracking-on-a-table-that-has-his-records-constantly-deleted-and-re