Create DML trigger for single table for a Database in SQL 2008R2

  • Create DML trigger for single table for a Database in SQL 2008R2

    Hi,

    I have a requirement to Create DML trigger for single table ( check for any Inserts, Updates & Delete ) in SQL 2008R2 and store Database Name, Event Type ,Object Name, TSQL to a different database. For example create Trigger on Database A Table and store result on Database B. I have the following the script to capture DML events on a Database, but it’s not sending result to B database.Any help would be greatly appreciated.

    Thanks in advance

    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

    ALTER trigger tr_trigtest on dbo.CER_SEDA_DOMAIN_A for insert, update, delete

    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)

    select @TableName = 'dbo.CER_SEDA_DOMAIN_A'

    -- date and user

    select @UserName = system_user ,

    @UpdateDate = convert(varchar(8), getdate(), 112) + ' ' + convert(varchar(12), getdate(), 114)

    -- 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

    fromINFORMATION_SCHEMA.TABLE_CONSTRAINTS pk ,

    INFORMATION_SCHEMA.KEY_COLUMN_USAGE c

    where pk.TABLE_NAME = @TableName

    andCONSTRAINT_TYPE = 'PRIMARY KEY'

    andc.TABLE_NAME = pk.TABLE_NAME

    andc.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 + '))+''>'''

    fromINFORMATION_SCHEMA.TABLE_CONSTRAINTS pk ,

    INFORMATION_SCHEMA.KEY_COLUMN_USAGE c

    where pk.TABLE_NAME = @TableName

    andCONSTRAINT_TYPE = 'PRIMARY KEY'

    andc.TABLE_NAME = pk.TABLE_NAME

    andc.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 CMMonitor.[dbo].Audit (Type, TableName, PK, FieldName, OldValue, NewValue, UpdateDate, UserName)'

    select @sql = @sql + ' select ''' + @Type + ''''

    select @sql = @sql + ',''' + @TableName + ''''

    select @sql = @sql + ',' + @PKSelect

    select @sql = @sql + ',''' + @fieldname + ''''

    select @sql = @sql + ',convert(varchar(1000),d.' + @fieldname + ')'

    select @sql = @sql + ',convert(varchar(1000),i.' + @fieldname + ')'

    select @sql = @sql + ',''' + @UpdateDate + ''''

    select @sql = @sql + ',''' + @UserName + ''''

    select @sql = @sql + ' from #ins i full outer join #del d'

    select @sql = @sql + @PKCols

    select @sql = @sql + ' where i.' + @fieldname + ' <> d.' + @fieldname

    select @sql = @sql + ' or (i.' + @fieldname + ' is null and d.' + @fieldname + ' is not null)'

    select @sql = @sql + ' or (i.' + @fieldname + ' is not null and d.' + @fieldname + ' is null)'

    exec (@sql)

    end

    end

    go

  • Did you verify your linked server permissions on the secondary database server to make sure it can actually access the database / table and write to it?

    EDIT: And are you sure your trigger is actually returning any values?

    Brandie Tarvin, MCITP Database AdministratorLiveJournal Blog: http://brandietarvin.livejournal.com/[/url]On LinkedIn!, Google+, and Twitter.Freelance Writer: ShadowrunLatchkeys: Nevermore, Latchkeys: The Bootleg War, and Latchkeys: Roscoes in the Night are now available on Nook and Kindle.

  • This is a difficult situation. The trigger you have created is trying to deal with a situation that I find to be very painful and not very useful in the long run. This Audit table will hold values for a given column along with the date it was modified. Here is the real issue with this type of design. Consider being asked to figure out all the values for a given primary key value on a given date. Think about how difficult this is going to be when you have a table with only 10 o 15 columns. You are going to have to write a big ugly nasty query just to determine the values for each column. Consider a much wider table and how difficult that is going to be.

    Now lets examine the actual trigger. There are some major issues with this trigger. Performance is going to be a serious issue here because of the complexity of what you are doing. You have built a while loop inside this trigger to insert a new row into the audit table for each column in CER_SEDA_DOMAIN_A. Looping in t-sql is almost always very slow.

    If this was a system I was working with I would consider rethinking the audit structure here and this can become a pretty simple process.

    For anybody else stumbling in here I formatted the posted code so we can see it easier.

    ALTER TRIGGER tr_trigtest ON dbo.CER_SEDA_DOMAIN_A

    FOR INSERT

    ,UPDATE

    ,DELETE

    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)

    SELECT @TableName = 'dbo.CER_SEDA_DOMAIN_A'

    -- date and user

    SELECT @UserName = system_user

    ,@UpdateDate = convert(VARCHAR(8), getdate(), 112) + ' ' + convert(VARCHAR(12), getdate(), 114)

    -- 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 CMMonitor.[dbo].Audit (Type, TableName, PK, FieldName, OldValue, NewValue, UpdateDate, UserName)'

    SELECT @sql = @sql + ' select ''' + @Type + ''''

    SELECT @sql = @sql + ',''' + @TableName + ''''

    SELECT @sql = @sql + ',' + @PKSelect

    SELECT @sql = @sql + ',''' + @fieldname + ''''

    SELECT @sql = @sql + ',convert(varchar(1000),d.' + @fieldname + ')'

    SELECT @sql = @sql + ',convert(varchar(1000),i.' + @fieldname + ')'

    SELECT @sql = @sql + ',''' + @UpdateDate + ''''

    SELECT @sql = @sql + ',''' + @UserName + ''''

    SELECT @sql = @sql + ' from #ins i full outer join #del d'

    SELECT @sql = @sql + @PKCols

    SELECT @sql = @sql + ' where i.' + @fieldname + ' <> d.' + @fieldname

    SELECT @sql = @sql + ' or (i.' + @fieldname + ' is null and d.' + @fieldname + ' is not null)'

    SELECT @sql = @sql + ' or (i.' + @fieldname + ' is not null and d.' + @fieldname + ' is null)'

    EXEC (@sql)

    END

    END

    GO

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