checking result of select statement

susi

Hi..

i was wondering if anyone could help me..

i have a form which enters information into the database if the id number is the same as in another database..

This works but im trying to have something that will tell the user that his registration has failed if the id is not the same..

Code is as follows:-

$father = "INSERT into father (id, forename, surname, addL1, addL2, postalCode, county) values ('$POST[id]', '$POST[forename]', '$POST[surname]', '$POST[addL1]', '$POST[addL2]', '$POST[postalCode]', '$POST[county]' where studs.id = '$POST[id]'";

echo $father;

mysql_query($father);

if(???????????????)
{
echo "Failed. Student Number is Invalid. Please try again.";
}
else
{
print(" Student Processed");
}

Is that even possible??!!

Any suggestions how to go about it??
Thanks
Susi

laserlight

do you mean table or database?

steadyguy

Try testing the number of rows affected with mysql_affected_rows():

if (mysql_affected_rows($father) >= 1) {
    //query succeeded do some stuff
}
else {
    //query failed ... do some other stuff
}

susi

Entering data into a table in a database.

Steadyguy - I tried your suggestion... i got the following error.

Warning: mysql_affected_rows(): supplied argument is not a valid MySQL-Link resource in c:\phpdev\www\4thyrproj\addingf.php on line 24

Not sure what to do to be honest... Only new at php..

Any suggestions? Thanks susi. 🙂

steadyguy

Realized my own mistake just now ...

mysql_affected_rows() takes a result handle ... you save the result handle returned by mysql_query() in a variable and test against that. Sorry about that.

In addition to that ... an INSERT query can't contain a WHERE clause ... though it is probably just ignored, and doesn't generate an error. You probably want an UPDATE query instead? If the update fails (ie., affects 0 rows, maybe generates an error), then you'll know the user does not have an entry in that table, and can act accordingly.

susi

im not sure i really understand..

how do i use update statement ..

i have two tables... one table has the id in it.. now this other table.. has nothing in it at the moment...

i want to be able to fill out a form and insert all the information ONLY if he enters an id that is already in the other table.

At the moment it inserts the information into the database but there is no checker..

I thought that the where would do that check!

Any ideas wat to do??
very stuck!

steadyguy

I see ... You will have to use a SELECT statement to check if the user has an ide in the main table:
SELECT id
    FROM {main_table}
    WHERE id="{some_id}"

If this query comes back empty (ie., mysql_num_rows($result_handle) == 0), then skip the update ... otherwise run your INSERT query (without theWHERE clause ('where studs.id = '$_POST[id]'").

Btw, you should always check user-supplied data to to make sure it is the kind of data you expect it to be. For example, If the student id (or stud id ... writing an app for breeding horses?) is supposed to be an 8-digit integer, for example, then you should make sure that it actually is an 8-digit integer, and not something like, 'uGotHact'.

susi

By the way.. thanks for all your help...
i tried something like what you said:-

$query = "SELECT id from studs where id = '$_POST[id]'";
echo $query;

$mysql_result = mysql_query($query);
$num_rows = mysql_num_rows($mysql_result);

if($num_rows == 0)
{
echo "Failed. Student Number is Invalid. Please try again.";
}
else
{
echo "CONGRATS!!! 🙂";

$father = "INSERT into father (id, forename, surname, addL1, addL2, postalCode, county, hNo, wNo, mobile, occup, employer) values ('$POST[id]', '$POST[forename]', '$POST[surname]', '$POST[addL1]', '$POST[addL2]', '$POST[postalCode]', '$POST[county]', '$POST[hNo]', '$POST[wNo]', '$POST[mobile]', '$POST[occup]', '$POST[employer]';

mysql_query($father);
}
?>

its not working... i get the following error:-

Parse error: parse error in c:\phpdev\www\4thyrproj\addingf.php on line 34

Line 34 being the last line in the program???!!

Any ideas or hav i totally messed it up???

susi

Thanks a million 4 everything!

Its all working now!!!

Thanks! 🙂