[RESOLVED] INSERT with loop fails.

[spookztar]

Hi guys,

I can't figure out why this, seemingly simple piece of code doesn't work, so I need an assist here. The dbname, host, username and password are all set, but I just get a blank browser window when I try this:

$query[] = "INSERT INTO parameter VALUES(1, 'dbname', '$dbname')";
$query[] = "INSERT INTO parameter VALUES(2, 'dbhost', '$dbhost')";
$query[] = "INSERT INTO parameter VALUES(3, 'dbusername', '$dbusername')";
$query[] = "INSERT INTO parameter VALUES(4, 'dbpassword', '$dbpassword')";
for ($nr = 0;$nr <=3;$nr++); {
mysql_query($query . $nr) or die("Error processing query $nr: '. mysql_error()";
}

[NogDog]

The first thing I see is that there is no closing paren for the die(). You might want to add the following lines to the top of the script while debugging so that you see that kind of error:

<?php
ini_set('display_errors', 1);
error_reporting(E_ALL);

[spookztar]

Still a blank screen, no messages...

[Houdini]

Might want to see what is really happening by doing this

for ($nr = 0;$nr <=3;$nr++); {
echo "<br />";
echo mysql_query($query . $nr) or die("Error processing query $nr: '. mysql_error()";

[spookztar]

"Error processing query 4: '. mysql_error()"

Query 4? It goes from 0-3... And why "mysql_error()" instead of outputting the error message? (I did include the last ")" for the die)

And why only error at 4? The table is still empty, so the previous ones must have failed as well.😕

This is a small portion of a larger script which works just fine. It collects the connection parameters from a selfsubmitting form, connects to the DB with them, and creates four tables. That all works fine, it's just the insertion of the parameters right after that fails. If you want to see the whole thing, just let me know.

[Houdini]

this

echo mysql_query($query . $nr) or die("Error processing query $nr: '. mysql_error()";

should be

echo mysql_query($query . $nr) or die("Error processing query $nr: ". mysql_error());

[NogDog]

$query[] = "INSERT INTO parameter VALUES(1, 'dbname', '$dbname')";
$query[] = "INSERT INTO parameter VALUES(2, 'dbhost', '$dbhost')";
$query[] = "INSERT INTO parameter VALUES(3, 'dbusername', '$dbusername')";
$query[] = "INSERT INTO parameter VALUES(4, 'dbpassword', '$dbpassword')";
for ($nr = 0;$nr <=3;$nr++); {
  mysql_query($query[$nr]) or die("Error processing query $nr: " . mysql_error());
}

A somewhat simpler way would be to user foreach:

$query[] = "INSERT INTO parameter VALUES(1, 'dbname', '$dbname')";
$query[] = "INSERT INTO parameter VALUES(2, 'dbhost', '$dbhost')";
$query[] = "INSERT INTO parameter VALUES(3, 'dbusername', '$dbusername')";
$query[] = "INSERT INTO parameter VALUES(4, 'dbpassword', '$dbpassword')";
foreach ($query as $sql) {
  mysql_query($sql) or die("Error processing query $nr: " . mysql_error());
}

[spookztar]

By the way guys, thanx for replying.

"foreach" could propably do it too, but what I've done should work just as well. Right? I'm generating a number from 0-3 and concatenating it with $query to create $query0 - 3 inside mysql_query(). Why does it fail? As far as the logic goes, I just can't see it's wrong. Now I HAVE to know.

If i use "foreach", I won't be needing the "[]" behind the four $query, correct?

We already fixed the paranthesis-thing Houdini...😉

[NogDog]

See the first part of my previous reply. You need to use an array variable - $query[$nr] - not just concatenate the two variables together.

[spookztar]

... But I still get the same error regardless NogDog.

I'll just try with "foreach".

EDIT: "Foreach" worked, but I'm still going to need to understand why the "for" version doesn't work, or else I'll have a VERY tough time learning how to program.😕

[NogDog]

Try some debug/defensive coding to see if you can locate the disconnect in the logic and/or syntax:

$query[] = "INSERT INTO parameter VALUES(1, 'dbname', '$dbname')";
$query[] = "INSERT INTO parameter VALUES(2, 'dbhost', '$dbhost')";
$query[] = "INSERT INTO parameter VALUES(3, 'dbusername', '$dbusername')";
$query[] = "INSERT INTO parameter VALUES(4, 'dbpassword', '$dbpassword')";
// START DEBUG:
printf("<h3>\$query array:</h3>\n<pre>%s</pre>\n", print_r($query, TRUE));
// END DEBUG
for ($nr = 0;$nr <=3;$nr++); {
   if(isset($query[$nr]))
   {
      mysql_query($query[$nr]) or 
      die("Error processing query $nr: {$query[$nr]}) - " . mysql_error());
   }
   else
   {
      user_error("\$query[$nr] is not set", E_USER_WARNING);
   }
}

[spookztar]

No error messages. All I got was:

query array

Array
(
    [0] => INSERT INTO parameter VALUES(1, 'dbname', 'mytest')
    [1] => INSERT INTO parameter VALUES(2, 'dbhost', 'localhost')
    [2] => INSERT INTO parameter VALUES(3, 'dbusername', 'root')
    [3] => INSERT INTO parameter VALUES(4, 'dbpassword', 'password')
)

I'm not an experienced programmer, but this to me, is redicilous. If this is what I can expect to be dealing with learning programming using PHP, perhaps Python is more the way to go. 😕

One little thing concerning foreach: Inside foreach condition specification, the "()" are excluded from $query. Why arent they needed?

[NogDog]

spookztar wrote:

No error messages. All I got was:
...

Have you checked the database to see if the records are being inserted? If they are, then the code is doing exactly what you told it to do. No where in there are you outputting anything that the user would see in the browser (other than debug info or error messages if things go wrong).

[spookztar]

It turned out that the reason I wasn't seeing anything, was because PHP itself had crashed... :xbones:

I ran it again and checked the parameter-table by logging on to mysql, and no inserts where completed. The table is still empty.

It just continues to give me "Error processing query 4: Query was empty" even though the number "4" isn't possible according to the conditionspecification of the "for". 😕

The reason why this is weirding me out is, that as far as logical coherence goes and theoretically as well, there is absolutely_nothing_wrong with the "for" example, nothing. :glare:

I'm flabbergasted.

[spookztar]

Solution here:

for ($nr=0;$nr<4;$nr++){
  mysql_query($query[$nr]) or die("Error processing query $nr: " . mysql_error());
}

Took out a semicolon, changed the exit logic (just because - I don't like less or equal, i just go for less than). May want to get your number of rows with a sizeof($nr) as well, just in case you end up adding something to it later.

It's incorrect syntax to have a semicolon after the closing bracket. What happened was the for loop executed what came after the brackets and before the semicolon, i.e a null statement, four times (0 - 3 inc) and then dropped down and printed out the next statement which was the error message. It printed out 4 because the <=3 condition allows the loop to execute an extra iteration to 4.

[NogDog]

Ooh...didn't see that sneaky little semi-colon you had there.

Anyway, you mark it resolved via the "Thread Tools" drop-down menu at the top of the thread.