Hi,

 

Im trying to create a constraint which will have a fixed length of 10.

The constraint i have used is:

CHAR(10)constraint

Now according to the books "CHAR" should be a fixed length, in my terms a fixed length of 10, however, i have just tried to insert some values consisting of 9 characters and it was accepted.

 

Do i need to add something to the constraint to allow the user to input exactly a fixed length of 10?

Hmm, I'm not sure about this, but I did a quick look on google for you:

 

http://www.devguru.com/Technologies/jetsql/quickref/constraint.html

 

This is Jet SQL so may be completely wrong, but apparently a constraint just limits what values you can put into your field, and perhaps reference other fields from different tables. Having not used it before, I'm not sure, but I don't think it's what you're after.

Using a constraint like char[10] makes 10 the MAXIMUM, to set a minimum requirement you'll need to script a checker onto the page.

Using a constraint like char[10] makes 10 the MAXIMUM,

 

i thougut varchar(2) sets a maximum length.

So what kind oif script checker do i need to check the length?

Varchar(2) is the same as CHAR(2) as far as this example is concerned

 

Like Faf says Ann, you need to validate the length of the string with a script before inserting it.

 

if (strlen($THE_STRING) == 10) {
 // do the insert query
} else {
 // send the user back to the form (or whatever)
 // add a warning message for good measure
}

Just a simple one to check the string length. A simple piece of Javascript would do it.

This is such a small check that it would be better to do it server-side rather than client-side, and thereby reduce the threat to platform independence.

True, although sometimes it's more convenient to do a client-side check if it's only small and supported by most browsers.

 

If you've got a big form for instance, then you don't want to have to re-insert all the information into your fields, and although this could be overcome with some more code on your server-side application, it's easier to write a couple lines of Javascript than 30 lines of php.

True, although it does depend how you parse the info.