Question : How to prevent duplicate records on the form UI?

I have a form, the query behind the form is like:
select field1, field2, field3, field4... field8 from tblTest
 
On the form, it's possible there are two records which have the same field values: field1 ... field 8.
 
How to prevent users from inserting duplicate records in the form (suppose not to change the table design)? Thanks.

Answer : How to prevent duplicate records on the form UI?

Fire 'SELECT' query before you actually insert the record. Traverse through the recordset returned by SELECT query and check if the field name already exists. If it does, show and error and if it doesn't call INSERT query.