Inserting into SQL table only if doesn't already exist?

[Kimmy4]

Hi guys,

(Using .net cf 2.0)
I have the following insert statement:

With sqlCmd
            .CommandText = "INSERT INTO photos(visitID, photoType, photoLocation, havePhoto)VALUES(@visitID, @photoType, @photoLocation, @havePhoto)"
            .Parameters.Add(New SqlCeParameter("@visitID", GetCurrentVisit()))
            .Parameters.Add(New SqlCeParameter("@photoLocation", photoLocation))
            .Parameters.Add(New SqlCeParameter("@photoType", photoType))
            .Parameters.Add(New SqlCeParameter("@havePhoto", "Y"))
            .ExecuteNonQuery()
            .Parameters.Clear()
        End With

But i only want it to do the insert if the value in photoLocation doesn't already exist?
How can i go about doing this?

Thanks in advance for any help