limiting number of entries to a table

[worp]

I am using a mysql database and using a simple form to input data into the table, but i want it to refuse the data if there is say 30 entries in the database already. Can anyone help me or point me into a tutorial on how to do this. Thanks

[Weedpacket]

So count the number of entries in the database, and don't add a new one if there are 30 already.