Warning: Mysqli_Query() Expects Parameter 1 To Be Mysqli, Null Given

[chiefboz]

Hello —

 

This is probably one of the most common mysqli errors out there, but it has appeared on my webpage. The problem is on line 10. This file is used as a global functions file - so I can essentially use db_query(INSERT INTO...) in a different page and have the function run.

 

For security reasons I have removed the actual usernames and such from the code, and it is pasted below. Any help would be greatly appreciated.

 

<?php
// Function to connect to the database.
function db_connect() {
$dbc = mysqli_connect('host','user','********','db');
}

// Function to run database queries.
function db_query($q) {
global $dbc;
$dbq = mysqli_query($dbc, $q); // ERROR OCCURS HERE
if(!$dbq) {
return false;
} else {
$r = mysqli_store_result($link);
}
}
?>

[haku]

You have your query and database connection backwards in your mysqli_query().

[chiefboz]

The function parameter $q gives it a query. For example, in another file register.php, I have

 

db_query("INSERT INTO user_accounts (firstname, lastname, email, username, reg_timestamp, verification_code, vcode_expire) VALUES ('$fn', '$ln', '$e1', '$un', $time, $v, $vcexp)");

 

where $fn, $ln, $e1 and $un are filled in by the user on a form. $time, $v and $vcexp are generated automatically.

 

The code above is just a function for use in other files.

[haku]

I edited my original comment, probably while you were posting, as I saw the error after I posted.

[chiefboz]

Ok, switched them, but that's a string (not a mysqli) and so it's still throwing errors.

[haku]

Yeah?

[PFMaBiSmAd]

The 1st parameter is the mysqli link.

 

The original error is because $dbc is not a global variable and doesn't exist outside of the db_connect(){} function. To get your existing code to 'work', you would need to return the connection resource from the db_connection() function and assign it to a $dbc variable in the main program's scope.

[haku]

Interesting, I didn't realize that mysqli_query() took the connection before the query.

 

But yeah, pmfbsad spotted the problem.

[chiefboz]

Ok, awesome, I got it resolved by combining the functions. Thank you!

[PFMaBiSmAd]

^^^ if by that you mean you are calling mysqli_connect() right before the mysqli_query() statement, don't. Creating a database connection is a fairly long process. You should not be making a database connection before each query. You should make ONE database connection and use it for the duration of the code on any one page.

[chiefboz]

Ok, cool, thanks for the tip. Problem solved.