how can i store records and if the record has already been entered

[SToRMBaNLeaDeR]

how can i enter data into a form then store that data in mysql and then if the person tries to make a duplicate entry then reject the duplicate entry or allow them to change the entry but ultimately not allow them to erase the entire previous entry

[coopster]

You need to either check for uniqueness prior to writing the entry or use the tools provided by the relational database management system to handle duplicate key processing.