Echa un vistazo a este artículo en Simple-talk.com por Pop Rivett. Lo guía a través de la creación de un disparador genérico que registrará el OLDVALUE y el NEWVALUE para todas las columnas actualizadas. El código es muy genérico y puede aplicarlo a cualquier tabla que desee auditar, también para cualquier operación CRUD, es decir, INSERTAR, ACTUALIZAR y ELIMINAR. El único requisito es que su tabla para ser auditada debe tener una CLAVE PRIMARIA (que la mayoría de las tablas bien diseñadas deberían tener de todos modos).
Aquí está el código relevante para su tabla GUESTS.
- Crear tabla AUDIT.
IF NOT EXISTS
(SELECT * FROM sysobjects WHERE id = OBJECT_ID(N'[dbo].[Audit]')
AND OBJECTPROPERTY(id, N'IsUserTable') = 1)
CREATE TABLE Audit
(Type CHAR(1),
TableName VARCHAR(128),
PK VARCHAR(1000),
FieldName VARCHAR(128),
OldValue VARCHAR(1000),
NewValue VARCHAR(1000),
UpdateDate datetime,
UserName VARCHAR(128))
GO
- CREE un activador de ACTUALIZACIÓN en la tabla INVITADOS de la siguiente manera.
CREATE TRIGGER TR_GUESTS_AUDIT ON GUESTS FOR UPDATE
AS
DECLARE @bit INT ,
@field INT ,
@maxfield INT ,
@char INT ,
@fieldname VARCHAR(128) ,
@TableName VARCHAR(128) ,
@PKCols VARCHAR(1000) ,
@sql VARCHAR(2000),
@UpdateDate VARCHAR(21) ,
@UserName VARCHAR(128) ,
@Type CHAR(1) ,
@PKSelect VARCHAR(1000)
--You will need to change @TableName to match the table to be audited.
-- Here we made GUESTS for your example.
SELECT @TableName = 'GUESTS'
-- date and user
SELECT @UserName = SYSTEM_USER ,
@UpdateDate = CONVERT (NVARCHAR(30),GETDATE(),126)
-- Action
IF EXISTS (SELECT * FROM inserted)
IF EXISTS (SELECT * FROM deleted)
SELECT @Type = 'U'
ELSE
SELECT @Type = 'I'
ELSE
SELECT @Type = 'D'
-- get list of columns
SELECT * INTO #ins FROM inserted
SELECT * INTO #del FROM deleted
-- Get primary key columns for full outer join
SELECT @PKCols = COALESCE(@PKCols + ' and', ' on')
+ ' i.' + c.COLUMN_NAME + ' = d.' + c.COLUMN_NAME
FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS pk ,
INFORMATION_SCHEMA.KEY_COLUMN_USAGE c
WHERE pk.TABLE_NAME = @TableName
AND CONSTRAINT_TYPE = 'PRIMARY KEY'
AND c.TABLE_NAME = pk.TABLE_NAME
AND c.CONSTRAINT_NAME = pk.CONSTRAINT_NAME
-- Get primary key select for insert
SELECT @PKSelect = COALESCE(@PKSelect+'+','')
+ '''<' + COLUMN_NAME
+ '=''+convert(varchar(100),
coalesce(i.' + COLUMN_NAME +',d.' + COLUMN_NAME + '))+''>'''
FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS pk ,
INFORMATION_SCHEMA.KEY_COLUMN_USAGE c
WHERE pk.TABLE_NAME = @TableName
AND CONSTRAINT_TYPE = 'PRIMARY KEY'
AND c.TABLE_NAME = pk.TABLE_NAME
AND c.CONSTRAINT_NAME = pk.CONSTRAINT_NAME
IF @PKCols IS NULL
BEGIN
RAISERROR('no PK on table %s', 16, -1, @TableName)
RETURN
END
SELECT @field = 0,
@maxfield = MAX(ORDINAL_POSITION)
FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = @TableName
WHILE @field < @maxfield
BEGIN
SELECT @field = MIN(ORDINAL_POSITION)
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = @TableName
AND ORDINAL_POSITION > @field
SELECT @bit = (@field - 1 )% 8 + 1
SELECT @bit = POWER(2,@bit - 1)
SELECT @char = ((@field - 1) / 8) + 1
IF SUBSTRING(COLUMNS_UPDATED(),@char, 1) & @bit > 0
OR @Type IN ('I','D')
BEGIN
SELECT @fieldname = COLUMN_NAME
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = @TableName
AND ORDINAL_POSITION = @field
SELECT @sql = '
insert Audit ( Type,
TableName,
PK,
FieldName,
OldValue,
NewValue,
UpdateDate,
UserName)
select ''' + @Type + ''','''
+ @TableName + ''',' + @PKSelect
+ ',''' + @fieldname + ''''
+ ',convert(varchar(1000),d.' + @fieldname + ')'
+ ',convert(varchar(1000),i.' + @fieldname + ')'
+ ',''' + @UpdateDate + ''''
+ ',''' + @UserName + ''''
+ ' from #ins i full outer join #del d'
+ @PKCols
+ ' where i.' + @fieldname + ' <> d.' + @fieldname
+ ' or (i.' + @fieldname + ' is null and d.'
+ @fieldname
+ ' is not null)'
+ ' or (i.' + @fieldname + ' is not null and d.'
+ @fieldname
+ ' is null)'
EXEC (@sql)
END
END
GO
