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Cómo crear vistas de historial o de auditoría a partir de tablas de captura de datos modificados (CDC) en SQL Server - Tutorial de SQL Server

Escenario:

Está trabajando como DBA o desarrollador de SQL Server, ha habilitado Change Data Capture en una de las bases de datos de SQL Server. Después de habilitar CDC, desea crear AUDIT O HIST Views para poder obtener los registros modificados.

Solución:

El siguiente script creará una vista para cada una de las tablas en las que CDC está habilitado en su base de datos. He usado Audit Schema, antes de ejecutar el script, debe crear Audit Schema o si desea crear vistas en Hist Schema, cambie Esquema en el siguiente código de Auditoría a Hist.
Cada vista nos devolverá debajo de las columnas
  • Tiempo_de_confirmación,
  • Nombre_Columna,
  • Valor_antiguo,
  • Nuevo_Valor,
  • Modificado por




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