how can I.......

Anon

get my program to recognise the double ID's that people might put in the database.
So do you know how I can prevent double value's in my dbase???

Thanks

Anon

I'm not sure what you're asking really. You might need to flesh out your question a bit for us to get what it is.

My guess is you need to learn how to use a UNIQUE constraint on a field in your database.

Anon

Yes I think so too, it's a bit difficult to explain this in an other language, because I don't even understand it in my own language hehe ;-)

But I would like to know how I can set my OrderID colomn in my dbase to unique, so that each orderID only exists 1 time in de dbase. I hope this is more clearly now.

I already crossed the option of "Unique" in my MySQL dbase. Now if I add a new OrderID with one that already exists in the dbase, then my program says, "Added succesfully", but when I go look, it isn't there. If I add a new OrderID with one that doesn't exists already in my database, then everything works fine, and the new OrderID is added.

Pretty strange if I my say so. I hope you will understand my question here, because it's very difficult to explain in english

Anon

you could check the orderID column for the value you are going to add. Then use the
function

$rows = mysql_num_rows($somevariable);

If it returns zero then add the value to the db else don't add the value.

hope this helps!

Sanj

Anon

Don't you have a primary key on the table that doesn't allow duplicates? If not, how are you doing the relating data with other tables ?

Anon

The easiest way to do this that I've found is to recreate the table then insert all the data back into it.

something like this (I use postgresql, so this may not work for you exactly, but you'll get the idea.)

create table yada (field1 text, field2 text, field3 int, orderid int unique);

This next one will NOT work in most flavors of mysql, but there's gotta something similar to it...

insert into yada values (select * from old table);

Anon

So, if two people open that page at the same time, how do you stop them from inserting the same orderid then? It's the databases job to ensure that you don't have duplicates. that way, you don't have to worry about these "race" conditions corrupting your data.