log UPDATEs to the column in a table

  • Hi,

    I have a log table time_log

    create table time_log(

    logID int identity (1,1) primary key

    ,taskID int

    ,userID varchar(16)

    ,logTable varchar(100)

    ,logColumn varchar(100)

    ,oldValue varchar(500)

    ,newValue varchar(500)

    ,insertedOn datetime default getdate()

    ,insertedBy varchar(32) default suser_sname()

    ,insertApplication varchar(128) default app_name()

    )

    On every UPDATE to most columns done to a table myTable, it needs to be logged into time_log table from a trigger.

    CREATE TABLE [dbo].[myTable](

    [user_id] [varchar](16) NOT NULL,

    [user_supervisor_id] [varchar](16) NULL,

    [user_name] [varchar](60) NOT NULL,

    [user_abbr] [varchar](8) NOT NULL,

    [rate_id] [int] NOT NULL,

    [user_active] [char](1) NOT NULL DEFAULT ('Y')

    ) ON [PRIMARY]

    GO

    INSERT myTable

    SELECT 1,'ASD','john',null,1,'N'

    UNION ALL

    SELECT 2,'DEF','miller','MI',2,'Y'

    UNION ALL

    SELECT 3,'FGH','San','KB',1,'Y'

    for this, i was trying like this inside a trigger

    if update(col_name)

    INSERT INTO time_log(....)values(...)

    the code will be repeated for each column,

    to avoid I used COALESCE like below

    CREATE TRIGGER dbo.myTable_OnUpdate

    ON dbo.myTable

    AFTER UPDATE AS

    --author name

    --test stuff

    BEGIN

    SET NOCOUNT ON

    DECLARE @sql VARCHAR(MAX)

    SELECT @sql=COALESCE(@SQL,'')+CAST('IF UPDATE(' + COLUMN_NAME + ')

    INSERT INTO dbo.time_log(taskID,userID,logTable,logColumn,oldValue,newValue)

    SELECT null,isnull(i.user_id,d.user_id),''myTable'','''+

    COLUMN_NAME+''',CAST(d.'+COLUMN_NAME+' AS VARCHAR),CAST(i.'+COLUMN_NAME+' AS VARCHAR)

    FROM inserted i join deleted d on i.user_id=d.user_id;

    '+char(10)+char(13) AS VARCHAR(MAX))

    FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = 'myTable'

    --PRINT @sql

    EXEC(@SQL)

    END

    Error:

    when i try to update the table

    update myTable

    set

    user_supervisor_id='XYZ'

    ,rate_id='3'

    ,user_active='Y'

    where user_id='3'

    i got the error

    Msg 140, Level 15, State 1, Line 1

    Can only use IF UPDATE within a CREATE TRIGGER statement.

    How Can I log in this way?

    Thanks,

    KB

    Thanks,
    Santhosh


    Human Knowledge Belongs To The World !!

  • You can't use IF UPDATE(column) in dynamic sql. If you don't want to type the code for each column, generate it and paste it into the trigger.

    You could also check for different columns between INSERTED (new values) and DELETED (old values).

    -- Gianluca Sartori

  • Is scripting and pasting in the trigger the only way to achieve this?

    Thanks,

    KB

    Thanks,
    Santhosh


    Human Knowledge Belongs To The World !!

Viewing 3 posts - 1 through 2 (of 2 total)

You must be logged in to reply to this topic. Login to reply