db trigger to avoid duplication of row ? how please

I'm Maintaining an existing website. Many times user clicked the button
twice, which results in duplication of row. now i cant do any modifications.
but i can write an trigger to check any row with same data,time stamp etc.
if so, then delete existing and insert new row with same data. but i do know
about trigger ? how can i achieve this validation using trigger.
Thnkz ,
Mahesh kumar.RCan't you use a UNIQUE constraint? For maintaining uniqueness that
would usually be the method preferred over a trigger.
David Portas
SQL Server MVP
--|||Why not define a primary key or unique constraint on the table?
Or, prevent the user from clicking the button twice, by disabling the
button, once it is pressed.
--
HTH,
Vyas, MVP (SQL Server)
SQL Server Articles and Code Samples @. http://vyaskn.tripod.com/
"~Maheshkumar.r" <mfcmahesh@.hotmail.com> wrote in message
news:%23CDz0EjJFHA.2772@.TK2MSFTNGP14.phx.gbl...
I'm Maintaining an existing website. Many times user clicked the button
twice, which results in duplication of row. now i cant do any modifications.
but i can write an trigger to check any row with same data,time stamp etc.
if so, then delete existing and insert new row with same data. but i do know
about trigger ? how can i achieve this validation using trigger.
Thnkz ,
Mahesh kumar.R