How to get updated column names in sql server

Question

I have a table called user with colums like FirstName,LastName,Age,Location,City,Education etc

What I wanted to do is

After a user Updates his information I wanted to track which are the columns that are updated by the user. Not the updated row but the exact columns in a particular row which are updated.

I have created an update trigger, but it not giving the exact result.

Thnaks,

Shibin

Answer 1

DECLARE @idTable INT
SELECT @idTable = T.id FROM sysobjects P JOIN sysobjects T ON P.parent_obj = T.id WHERE P.id = @@procid
DECLARE @Columns_Updated VARCHAR(50)

SELECT  @Columns_Updated = ISNULL(@Columns_Updated + ', ', '') + name
FROM    syscolumns
WHERE   id = @idTable
AND     CONVERT(VARBINARY,REVERSE(COLUMNS_UPDATED())) & POWER(CONVERT(BIGINT, 2), colorder - 1)  > 0

Answer 2

/*******************************************************************************************
*         Add the below table to your database to track data changes using the trigger    *
*         below. Remember to change the variables in the trigger to match the table that  *
*         will be firing the trigger                                                      *
*******************************************************************************************/
SET ANSI_NULLS ON;
GO

SET QUOTED_IDENTIFIER ON;
GO

CREATE TABLE [dbo].[AuditDataChanges]
(
  [RecordId] [INT] IDENTITY(1, 1)
                   NOT NULL ,
  [TableName] [VARCHAR](50) NOT NULL ,
  [RecordPK] [VARCHAR](50) NOT NULL ,
  [ColumnName] [VARCHAR](50) NOT NULL ,
  [OldValue] [VARCHAR](50) NULL ,
  [NewValue] [VARCHAR](50) NULL ,
  [ChangeDate] [DATETIME2](7) NOT NULL ,
  [UpdatedBy] [VARCHAR](50) NOT NULL ,
  CONSTRAINT [PK_AuditDataChanges] PRIMARY KEY CLUSTERED
    ( [RecordId] ASC )
    WITH ( PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF,
           IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON,
           ALLOW_PAGE_LOCKS = ON ) ON [PRIMARY]
)
ON  [PRIMARY];

GO

ALTER TABLE [dbo].[AuditDataChanges] ADD  CONSTRAINT   [DF_AuditDataChanges_ChangeDate]  DEFAULT (GETDATE()) FOR [ChangeDate];
GO



/************************************************************************************************
* Add the below trigger to any table you want to audit data changes on. Changes will be saved   *
* in the  AuditChangesTable.                                                                    *
*************************************************************************************************/
ALTER TRIGGER trg_Survey_Identify_Updated_Columns ON Survey --Change to match your table name
FOR INSERT, UPDATE
AS
SET NOCOUNT ON;

DECLARE @sql VARCHAR(5000) ,
    @sqlInserted NVARCHAR(500) ,
    @sqlDeleted NVARCHAR(500) ,
    @NewValue NVARCHAR(100) ,
    @OldValue NVARCHAR(100) ,
    @UpdatedBy VARCHAR(50) ,
    @ParmDefinitionD NVARCHAR(500) ,
    @ParmDefinitionI NVARCHAR(500) ,
    @TABLE_NAME VARCHAR(100) ,
    @COLUMN_NAME VARCHAR(100) ,
    @modifiedColumnsList NVARCHAR(4000) ,
    @ColumnListItem NVARCHAR(500) ,
    @Pos INT ,
    @RecordPk VARCHAR(50) ,
    @RecordPkName VARCHAR(50);

SELECT  *
INTO    #deleted
FROM    deleted;
SELECT  *
INTO    #Inserted
FROM    inserted;

SET @TABLE_NAME = 'Survey'; ---Change to your table name
SELECT  @UpdatedBy = UpdatedBy --Change to your column name for the user update field
FROM    inserted;
SELECT  @RecordPk = SurveyId --Change to the table primary key field
FROM    inserted;   
SET @RecordPkName = 'SurveyId';
SET @modifiedColumnsList = STUFF(( SELECT   ',' + name
                                   FROM     sys.columns
                                   WHERE    object_id = OBJECT_ID (@TABLE_NAME)
                                            AND SUBSTRING(COLUMNS_UPDATED(),
                                                          ( ( column_id
                                                          - 1 ) / 8 + 1 ),
                                                          1) & ( POWER(2,
                                                          ( ( column_id
                                                          - 1 ) % 8 + 1 )
                                                          - 1) ) = POWER(2,
                                                          ( column_id - 1 )
                                                          % 8)
                                 FOR
                                   XML PATH('')
                                 ), 1, 1, '');


WHILE LEN(@modifiedColumnsList) > 0
    BEGIN
        SET @Pos = CHARINDEX(',', @modifiedColumnsList);
        IF @Pos = 0
            BEGIN
                SET @ColumnListItem = @modifiedColumnsList;
            END;
        ELSE
            BEGIN
                SET @ColumnListItem = SUBSTRING(@modifiedColumnsList, 1,
                                                @Pos - 1);
            END;    

        SET @COLUMN_NAME = @ColumnListItem;
        SET @ParmDefinitionD = N'@OldValueOut NVARCHAR(100) OUTPUT';
        SET @ParmDefinitionI = N'@NewValueOut NVARCHAR(100) OUTPUT';
        SET @sqlDeleted = N'SELECT @OldValueOut=' + @COLUMN_NAME
            + ' FROM #deleted where ' + @RecordPkName + '='
            + CONVERT(VARCHAR(50), @RecordPk);
        SET @sqlInserted = N'SELECT @NewValueOut=' + @COLUMN_NAME
            + ' FROM #Inserted where ' + @RecordPkName + '='
            + CONVERT(VARCHAR(50), @RecordPk);
        EXECUTE sp_executesql @sqlDeleted, @ParmDefinitionD,
            @OldValueOut = @OldValue OUTPUT;
        EXECUTE sp_executesql @sqlInserted, @ParmDefinitionI,
            @NewValueOut = @NewValue OUTPUT;
        IF ( LTRIM(RTRIM(@NewValue)) != LTRIM(RTRIM(@OldValue)) )
            BEGIN   
                SET @sql = 'INSERT INTO [dbo].[AuditDataChanges]
                                               ([TableName]
                                               ,[RecordPK]
                                               ,[ColumnName]
                                               ,[OldValue]
                                               ,[NewValue]
                                               ,[UpdatedBy])
                                         VALUES
                                               (' + QUOTENAME(@TABLE_NAME, '''') + '
                                               ,' + QUOTENAME(@RecordPk, '''') + '
                                               ,' + QUOTENAME(@COLUMN_NAME, '''') + '
                                               ,' + QUOTENAME(@OldValue, '''') + '
                                               ,' + QUOTENAME(@NewValue, '''') + '
                                               ,' + QUOTENAME(@UpdatedBy, '''') + ')';


                EXEC (@sql);
            END;     
        SET @COLUMN_NAME = '';
        SET @NewValue = '';
        SET @OldValue = '';
        IF @Pos = 0
            BEGIN
                SET @modifiedColumnsList = '';
            END;
        ELSE
            BEGIN
           -- start substring at the character after the first comma
                SET @modifiedColumnsList = SUBSTRING(@modifiedColumnsList,
                                                     @Pos + 1,
                                                     LEN(@modifiedColumnsList)
                                                     - @Pos);
            END;
    END;
DROP TABLE #Inserted;
DROP TABLE #deleted;

GO