Сценарий:Изтегляне на скрипт
Понякога трябва да добавим или пуснем колона към таблицата с източник, за която вече е активирано улавянето на промяна на данни (CDC).Новата добавена колона няма да бъде проследена от улавянето на промяна на данни (CDC), а за изпусната колона CDC таблицата ще show Null.
SP може да се използва за добавяне на нова колона към промяна на събирането на данни (CDC), без да се губят каквито и да било предишни данни в таблицата на CDC. Същият SP може да се използва за премахване на колона от Change Data Capture (CDC), тъй като тя се отстранява от колона източник, но оставя останалите колони без загуба на данни в CDC таблицата.
USE [DataBaseName]
GO
/*--------------------------------------------------------------------------------------------------------
How to Execute: EXEC usp_AddOrDropColumnToCDCTableWithoutLosingData @SchemaName,@TableName,@ColumnName,@Action
Adding New Column
Example :EXEC usp_AddOrDropColumnToCDCTableWithoutLosingData 'dbo','T','NAME','ADD'
Drop existing Column
Example :EXEC usp_AddOrDropColumnToCDCTableWithoutLosingData 'dbo','T','Name','DROP'
--------------------------------------------------------------------------------------------------------*/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE PROCEDURE dbo.Usp_addordropcolumntocdctablewithoutlosingdata @pSchemaName VARCHAR(50),
@pTableName VARCHAR(100),
@pColumnName VARCHAR(100),
@pAction VARCHAR(10)
AS
BEGIN
DECLARE @vSQLTempTable NVARCHAR(MAX)
DECLARE @vSQLAlterTable NVARCHAR(MAX)
DECLARE @vDisableCDC NVARCHAR(MAX)
DECLARE @vGetAlreadyExistingColumns NVARCHAR(MAX)
DECLARE @vEnableCDC NVARCHAR(MAX)
DECLARE @vLoadCDCTable NVARCHAR(MAX)
DECLARE @vDropCreateTemp NVARCHAR(MAX)
DECLARE @vDataType VARCHAR(50)
DECLARE @vColumnList NVARCHAR(2000)
DECLARE @vColumnExists INT
DECLARE @vColumnExistsCDC INT
DECLARE @vTempTableName VARCHAR(100)
DECLARE @vDropColumnList NVARCHAR(2000)
DECLARE @vDropColumnListExcSys NVARCHAR(2000)
SET @vTempTableName='##' + @pSchemaName + '_' + @pTableName
BEGIN TRY
IF ( @pAction = 'ADD'
OR @pAction = 'Drop' )
BEGIN
--Check if Column exists for SourceTable table
SET @vColumnExists=(SELECT Count(*)
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_SCHEMA = @pSchemaName
AND TABLE_NAME = @pTableName
AND COLUMN_NAME = @pColumnName)
IF ( @vColumnExists = 0
AND @pAction = 'ADD' )
BEGIN
PRINT ' COLUMN ::' + @pColumnName
+ ' does not exists for Source Table ::'
+ @pTableName
+ ' Please add column to Source Table to include in CDC Table.'
END
ELSE
BEGIN
PRINT ' COLUMN ::' + @pColumnName
+ ' exists for Source Table ::' + @pTableName
+ '-->Proceeding to Next Step.'
END
--Check if Column exists for CDC table
IF ( @vColumnExists != 0
AND @pAction = 'ADD' )
SET @vColumnExistsCDC=(SELECT Count(*)
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_SCHEMA = 'cdc'
AND TABLE_NAME = @pSchemaName + '_' + @pTableName + '_CT'
AND COLUMN_NAME = @pColumnName)
IF ( @vColumnExistsCDC != 0
AND @pAction = 'ADD' )
BEGIN
PRINT ' COLUMN ::' + @pColumnName
+ ' is already part of CDC Tble ::cdc.'
+ @pSchemaName + '_' + @pTableName + 'CT'
END
IF ( @vColumnExistsCDC = 0
AND @pAction = 'ADD' )
BEGIN
PRINT ' COLUMN ::' + @pColumnName
+ ' is not part of CDC Tble ::cdc.'
+ @pSchemaName + '_' + @pTableName
+ 'CT -->Proceeding to ADD this column'
END
--COPY EXISTING CDC TABLE TO TEMP TABLE
--Drop Temp table before Creating/Loading IT
SET @vDropCreateTemp=' IF Object_id(N''tempdb..'
+ @vTempTableName
+ ''') IS NOT NULL
BEGIN
DROP TABLE ##'
+ @pSchemaName + '_' + @pTableName + ' END'
PRINT @vDropCreateTemp
EXEC (@vDropCreateTemp)
SET @vSQLTempTable= 'SELECT * INTO ' + @vTempTableName
+ ' From cdc.' + @pSchemaName + '_' + @pTableName
+ '_CT'
PRINT @vSQLTempTable
EXEC(@vSQLTempTable)
IF ( @vColumnExistsCDC = 0
AND @pAction = 'ADD' )
BEGIN
--ADD COLUMN TO TEMP TABLE
SET @vDataType=(SELECT CASE
WHEN DATA_TYPE IN ( 'CHAR', 'varchar', 'nvarchar' ) THEN DATA_TYPE + '('
+ Cast(CHARACTER_MAXIMUM_LENGTH AS VARCHAR(50))
+ ')'
WHEN Data_Type IN ( 'int', 'bigint', 'smallint', 'tinyint',
'money', 'bit', 'date', 'datetime' ) THEN Data_Type
WHEN data_type IN ( 'numeric', 'decimal' ) THEN DATA_TYPE + '('
+ Cast(Numeric_Precision_Radix AS VARCHAR(50))
+ ',' + Cast(Numeric_scale AS VARCHAR(50))
+ ')'
END AS DataType
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = @pTableName
AND COLUMN_NAME = @pColumnName)
SET @vSQLAlterTable='ALTER TABLE ' + @vTempTableName + ' ADD '
+ @pColumnName + ' ' + @vDataType
PRINT @vSQLAlterTable
EXEC (@vSQLAlterTable)
-- ENABLE CDC ON TABLE ( INCLUDING NEW COLUMN)
IF Object_id(N'tempdb..##ColumnList') IS NOT NULL
BEGIN
DROP TABLE ##ColumnList
END
CREATE TABLE ##ColumnList
(
ColumnList NVARCHAR(2000)
)
SET @vGetAlreadyExistingColumns= N' DECLARE @vCDCAlreadyEnabledColumns NVARCHAR(2000)
SELECT @vCDCAlreadyEnabledColumns = COALESCE(@vCDCAlreadyEnabledColumns+ '','', '''')
+ QUOTENAME(COLUMN_NAME) FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME='''
+ @pSchemaName + '_' + @pTableName + '_'
+ 'CT'' AND COLUMN_NAME NOT
IN (''__$start_lsn'',
''__$end_lsn'',
''__$seqval'',
''__$operation'',
''__$update_mask'')
PRINT @vCDCAlreadyEnabledColumns
Insert into ##ColumnList values (@vCDCAlreadyEnabledColumns)'
PRINT @vGetAlreadyExistingColumns
EXEC ( @vGetAlreadyExistingColumns)
SELECT @vColumnList = ColumnList + ',[' + @pColumnName + ']'
FROM ##ColumnList
PRINT @vColumnList
-- DISABLE CDC ON SOURCE TABLE
SET @vDisableCDC='EXEC sys.sp_cdc_disable_table @source_schema='''
+ @pSchemaName + ''',
@source_name='''
+ @pTableName + ''',@capture_instance='''
+ @pSchemaName + '_' + @pTableName + ''''
PRINT @vDisableCDC
EXEC (@vDisableCDC)
--Enable CDC
SET @vEnableCDC='EXEC sys.sp_cdc_enable_table
@source_schema=''' + @pSchemaName
+ ''',@source_name=''' + @pTableName
+ ''', @role_name=NULL, @captured_column_list= '''
+ @vColumnList + ''''
PRINT @vEnableCDC
EXEC (@vEnableCDC)
-- INSERT RECORD FROM Temp to CDC Table
SET @vLoadCDCTable=' INSERT INTO cdc.' + @pSchemaName + '_'
+ @pTableName
+ '_CT
SELECT * FROM '
+ @vTempTableName + ''
-- Drop Table '+@vTempTableName+''
PRINT @vLoadCDCTable
EXEC (@vLoadCDCTable)
END
/***-------------------------------------DROP COLUMN LOGIC STARTS-----------------------------************/
--Build Column List excluding Drop column
IF EXISTS (SELECT 1
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_SCHEMA = 'cdc'
AND TABLE_NAME = @pSchemaName + '_' + @pTableName + '_CT'
AND COLUMN_NAME = @pColumnName)
AND @pAction = 'Drop'
BEGIN
SELECT @vDropColumnList = Stuff(o.COLUMNNAME, 1, 1, '')
FROM INFORMATION_SCHEMA.COLUMNS t
CROSS APPLY (SELECT ',' + Column_Name + Char(10) AS [text()]
FROM INFORMATION_SCHEMA.COLUMNS c
WHERE c.Table_Name = t.Table_Name
AND c.COLUMN_NAME <> @pColumnName
FOR XML PATH('')) o (COLUMNNAME)
WHERE t.Table_Name = 'dbo_' + @pTableName + '_CT'
--Get Columns without Sytem Columns
SELECT @vDropColumnListExcSys = Stuff(o.COLUMNNAME, 1, 1, '')
FROM INFORMATION_SCHEMA.COLUMNS t
CROSS APPLY (SELECT ',' + Column_Name + Char(10) AS [text()]
FROM INFORMATION_SCHEMA.COLUMNS c
WHERE c.Table_Name = t.Table_Name
AND c.COLUMN_NAME <> @pColumnName
AND C.COLUMN_NAME NOT IN ( '__$start_lsn', '__$end_lsn', '__$seqval', '__$operation', '__$update_mask' )
FOR XML PATH('')) o (COLUMNNAME)
WHERE t.Table_Name = 'dbo_' + @pTableName + '_CT'
-- DISABLE CDC for Drop Column
SET @vDisableCDC='EXEC sys.sp_cdc_disable_table @source_schema='''
+ @pSchemaName + ''',
@source_name='''
+ @pTableName + ''',@capture_instance='''
+ @pSchemaName + '_' + @pTableName + ''''
EXEC (@vDisableCDC)
-- ENABLE TABLE EXCLUDING GIVEN COLUMN
SET @vEnableCDC='EXEC sys.sp_cdc_enable_table
@source_schema=''' + @pSchemaName
+ ''',@source_name=''' + @pTableName
+ ''', @role_name=NULL, @captured_column_list= '''
+ @vDropColumnListExcSys + ''''
EXEC (@vEnableCDC)
--COPY DATA FROM TEMP DATA TO CDC TABLE
SET @vLoadCDCTable=' INSERT INTO cdc.' + @pSchemaName + '_'
+ @pTableName + '_CT(' + @vDropColumnList
+ ')
SELECT '
+ @vDropColumnList + ' FROM ' + @vTempTableName
+ ''
--Drop Table '+@vTempTableName+''
EXEC (@vLoadCDCTable)
END
END
ELSE
PRINT ' ADD OR Drop are the correct actions available for this Procedure.Please provide ADD or Drop for SP Signature'
END TRY
BEGIN CATCH
ROLLBACK
PRINT ' ERROR Occured and All Transactions are rolledback.'
END CATCH
END 
