How to Create History OR Audit Views from Change Data Capture ( CDC) Tables in SQL Server - SQL Server Tutorial

Scenario:

You are working as SQL Server DBA or developer, you have enabled Change Data Capture on one of the SQL Server Database, After enabling CDC you  want to create AUDIT OR HIST Views

so  can get the changed records. 

Solution:

The below script will create view for each of the table on which CDC is enabled in your database.

I have used Audit Schema, before you run the script, You need to create Audit Schema or If you want to create views in Hist Schema then change Schema in Below Code from Audit To Hist.

Each view will return us below columns 

• Commit_Time,
• Colum_Name,
• Old_Value,
• New_Value,
• ModifiedBy

IF OBJECT_ID(N'tempdb..##CDC_TableList') IS NOT NULL

BEGIN
    DROP TABLE ##CDC_TableList

END

SELECT T.name AS TableName,
       C.name AS ColumnName,
       'CASE WHEN (sys.Fn_cdc_is_bit_set (sys.Fn_cdc_get_column_ordinal (''dbo_'
       + T.name + ''',''' + C.name+
       + '''),__$update_mask) = 1) THEN Cast('
       + C.Name
       + ' AS SQL_VARIANT) ELSE NULL END AS '
       + C.name  AS CaseStm INTO ##CDC_TableList

 FROM   sys.tables T
       INNER JOIN sys.columns c
               ON T.OBJECT_ID = c.OBJECT_ID

WHERE  is_tracked_by_cdc = 1
       AND c.is_identity = 0
       AND C.name NOT IN ( 'CreatedBy', 'CreatedDate', 'ModifiedBy', 'ModifiedDate' )
       AND T.TYPE='U'
       AND T.is_ms_shipped<>1
      
      -- Select * from sys.tables

DECLARE @TableName NVARCHAR(200)

DECLARE cdc_cursor CURSOR FOR 
SELECT DISTINCT TableName FROM ##CDC_TableList

OPEN cdc_cursor 

FETCH NEXT FROM cdc_cursor INTO @TableName

WHILE @@FETCH_STATUS = 0 

BEGIN

DECLARE @ColumnList  NVARCHAR(MAX)

DECLARE @CaseStmList NVARCHAR(MAX)

DECLARE @SQL_Stm  NVARCHAR(MAX)

DECLARE @SQL_Stm_DropView  NVARCHAR(MAX)

PRINT @TableName

 SELECT @ColumnList = STUFF(o.COLUMNNAME, 1, 1, '')
 FROM ##CDC_TableList t CROSS APPLY  (SELECT ',' + ColumnName+CHAR(10) AS [text()]
            FROM  ##CDC_TableList c
            WHERE    c.TableName = t.TableName
            FOR XML PATH('')) o (COLUMNNAME)
 WHERE t.TableName=@TableName
 PRINT @ColumnList
 
 SELECT @CaseStmList = STUFF(o.COLUMNNAME, 1, 1, '')
 FROM ##CDC_TableList t CROSS APPLY  (SELECT ',' + CaseStm+CHAR(10) AS [text()]
            FROM  ##CDC_TableList c
            WHERE    c.TableName = t.TableName
            FOR XML PATH('')) o (COLUMNNAME)
 WHERE t.TableName=@TableName
 --PRINT @CaseStmList


--If using Other Schema than AUDIT THEN change to that.
SET @SQL_Stm=' CREATE VIEW AUDIT.vw_'+@TableName+' AS

SELECT sys.Fn_cdc_map_lsn_to_time(up_b.__$start_lsn) AS Commit_Time, up_b.Column_Name, up_b.Old_Value, up_a.New_Value,up_a.ModifiedBy
FROM
    ( SELECT __$start_lsn, column_name, old_value,ModifiedBy
   FROM (SELECT __$start_lsn,'+@CaseStmList+',ModifiedBy FROM cdc.fn_cdc_get_all_changes_dbo_'+@TableName+'( sys.fn_cdc_get_min_lsn(''dbo_'+@TableName+'''), sys.fn_cdc_map_time_to_lsn(''largest less than or equal'',GETDATE()), N''all update old'')
 WHERE __$operation = 3
  ) AS BeforeUpdate
  UNPIVOT (old_value FOR column_name IN ('+@ColumnList+') ) AS unp) AS up_b INNER JOIN
  (SELECT __$start_lsn, column_name, new_value,ModifiedBy
   FROM (SELECT __$start_lsn,'+@CaseStmList+',ModifiedBy FROM cdc.fn_cdc_get_all_changes_dbo_'+@TableName+'(sys.fn_cdc_get_min_lsn(''dbo_'+@TableName+'''), sys.fn_cdc_map_time_to_lsn(''largest less than or equal'',GETDATE()), N''all'')
    WHERE __$operation = 4
   ) AS AfterUpdate
   UNPIVOT (new_value FOR column_name IN ('+@ColumnList+') ) AS unp ) AS up_a
ON up_b.__$start_lsn = up_a.__$start_lsn AND up_b.column_name = up_a.column_name'
--Drop View if already exists
SET @SQL_Stm_DropView= 'IF EXISTS (SELECT TABLE_NAME FROM INFORMATION_SCHEMA.VIEWS
         WHERE TABLE_NAME = ''vw_'+@TableName+''')
   DROP VIEW AUDIT.vw_'+@TableName
   PRINT @SQL_Stm_DropView

EXEC (@SQL_Stm_DropView)

EXEC ( @SQL_Stm)

FETCH NEXT FROM cdc_cursor INTO @TableName

END 

CLOSE cdc_cursor 
DEALLOCATE cdc_cursor