PHP/Mysql checking for duplicates during insert?

I have an online database that allows users to enter data.

Is there a way I can verify that they do not enter a duplicate?
I would have to check it with at least three fields. Date and Name
and state

Thanks for any information.

"MeNotHome" <dtfa@****nospm****insightbb.com> wrote in message
news:oobogvsiinn8pm44uiq2i8j7jhruvl3n8e@4ax.com...
> I have an online database that allows users to enter data.
>
> Is there a way I can verify that they do not enter a duplicate?
> I would have to check it with at least three fields. Date and Name
> and state
>
> Thanks for any information.
>
>

Do these users enter data directly into the database or via a form on a web
page?

If it's a form, use PHP to validate the fileds:

if ($field01 = '' || $field02 == '' || $field03 == '') {
echo "field01 and field02 and field03 have not been filled in...";
}
else {
// process form
}

$sql = "SELECT * from table WHERE date = '$date' and name = '$name' and
state = '$state'";
if (mysql_num_rows($sql_query)==0) {
insert
} else {
don't insert
}

"MeNotHome" <dtfa@****nospm****insightbb.com> wrote in message
news:oobogvsiinn8pm44uiq2i8j7jhruvl3n8e@4ax.com...
> I have an online database that allows users to enter data.
>
> Is there a way I can verify that they do not enter a duplicate?
> I would have to check it with at least three fields. Date and Name
> and state
>
> Thanks for any information.
>
>