mysql_query in OOP. Im new to this.

[acefirefighter]

I am getting a "mysqli_query() expects parameter 1 to be mysqli, null given" error.

 

the code I am using is below but simplified. connect() does connect to the database without throwing any errors but when I get down to query() I get the above error.

 

	public function connect() {
 	mysqli_connect(self::DBHOST, self::DBUSER, self::DBPASS, self::DBNAME);
}
public function query($query) {
                 mysqli_query(self::connect(), $query);
}

 

below is what I am using to call the function. I am not sure if I have to pass the $link in the query function too. I have tried but it didn't seem to do any better.

$link = db::connect();

$query = "SELECT name FROM plugins";

db::query($query);

 

I am sure this is something simple that I have overlooked but I am new to this and still learning.

 

Thank you for any help you can provide.

[Mchl]

You should take a look at implementing a singleton pattern for this class. As it is now it doesn't make much sense.

 

 

[acefirefighter]

Thanks for the fast reply. Looked into the singleton pattern and I think I have done pretty well sticking to that but I am new so I can't always be sure. I gave snippets of my code and that may have been my mistake. Ill include it all in this post.

 

<?php
class db extends config { // config defines the login info for the database


// open a database connection
public function connect() { 
// all of the connection parameters are defined elsewhere and I can connect without errors.
 	mysqli_connect(self::DBHOST, self::DBUSER, self::DBPASS, self::DBNAME);
}// query the database
public function query($query) {// this is where the error is being thrown
	mysqli_query(self::connect(), $query);
}
}

$query = "SELECT name FROM user";

db::query($query);

 

[Mchl]

Mmm... not really... this code is not even valid...

 

 

How about like this:

 

class dbConnection {

  private static $mysql;

  public static get() {
    if(!isset(self::$mysql)) {
      //this is a bit ugly - an implicit dependency on config class
      self::$mysql = new mysqli(config::DBHOST, config::DBUSER, config::DBPASS, config::DBNAME);
    } 
    return self::$mysql;
  }
}

 

And you use it like this:

 

$mysql = dbConnection::get();
$query = "SELECT name FROM user";
$result = $mysql->query($query);
...

[acefirefighter]

OK. I have spent an hour or so looking over the code you sent me. I think it's so simple it didn't quite make sense at first. I do get it now though.

 

As you said a dependency on the config class isn't the best idea. What would you suggest?

Setting the connection credentials in the dbConnection class???