Checking for duplicate prior to appending

[roelandkim]

Hi all,

One of the buttons on a form I have runs an append query which appends a specific client record to a new table, dbo_Tbl_ParticipantData. I would like the OnClick event to trigger a lookup into this new table to see if the record already exists based on SSN. What is the best way to do this? Below is the append query.

INSERT INTO dbo_Tbl_ParticipantData ( FirstName, SSN, LastName, ElitePK )
SELECT Qry_osEntityFormat.FirstName, Qry_osEntityFormat.TaxID, Qry_osEntityFormat.LastName, Qry_osEntityFormat.osEntityFormat
FROM Qry_osEntityFormat
WHERE (((Qry_osEntityFormat.TaxID)=[Enter SSN]));

 

[Pat Hartman]

When most of the time, SSN will not be duplicated, it is inefficient to validate it. It is much more efficient to define a unique index on SSN and let the database engine do the work.