Preventing Multiple Identical Entries

i guyz,

i want to know how i can prevent my program from entering the same entry when i refresh the page?

Here's my code:

the form:

the course_man page:

 

Hiya...hard to read .

My suggestions:
1. After submit data, redirect to other page, or
2. When submit data, check is it some content of the input already inserted or not? SELECT * WHERE content = $_POST['content'] or something like that.

 

You could add a primary key on the database table so that only 1 value may be inserted. Any insert with the same value will fail.

 

Or make unique, but that's not realy handy.

To prevent do not SELECT * but one field, you just want to check if something exists nothing more!