Can anyone see in this code why my insert and check username function is not working?

Question

Hi guys.
I have an error that has me stumped.
I have a form that inserts text from a text field into a
mysql database and I have added a check user name function to check
if this number already exists.
Here's the page
http://www.thechallenge.net.au/redemption2.php
The error I get when using the page on the web is this
Duplicate entry '' for key 1
Can anyone help with this?

Answer 1

ducati1 wrote:
> Ok we are now getting somewhere.
> I have reset the mysql database as recommended and
everything works Except the
> pay pal receipt number is being entered into the
database as only numbers and
> no letters. For example when I entered 123456f it went
to the database as
> 123456 with no "f".
> What should I set the database and text field properties
to so it records all
> that might be in a pay pal receipt number?
I noticed previously you changed it to int, that means
integer, which is
a numeric datatype.
You want mixed characters and numbers? Is it always the same
length? If
it is, use a CHAR datatype and set it to the length you need,
CHAR(12)
for instance will let you use 12 characters. Even if the
number entered
isn't 12 characters, it will be stored as 12 characters, but
with spaces
where there are no characters. I personally never use this
unless I am
100% certain that its going to be exactly the same length,
otherwise
doing comparisons is problematic, as you need to TRIM the
white space.
If the length is going to vary, then use VARCHAR(12), this
let you use
up to 12 characters. It won't put extra spaces in. This is my
preference.
Now, if you are also storing double byte characters, like
foreign
characters, you might want to consider using NVARCHAR or
NCHAR.
Oh, these examples are based on MS SQL datatypes, so MySQL
might be
slightly different, so it may be worth checking the manual
first.
Dooza