PHP OOP MySQL Programming

Question

I am a beginner in PHP programming and would like help with a little question. Please take a look at the code below:

PHP Code

<?php
class Account
{
  public function register()
  {
    $db_link = mysql_connect("localhost","root","");  // Create Connection
    if (!$db_link)  // Check connection
    {
      die(mysql_error());
    }

    mysql_close($db_link); // Close Connection
  }

  public function login()
  {
    $con = mysql_connect("localhost","root","")  // create connection
    if (!$con)  // create connection
    {
      die(mysql_error());
    }
    mysql_close($con); //close connection
  }

}
?>

My question is if creating individual db links for every single one of the object's methods is the best way to go? Is there a better or alternative way to do this? Hopefully I've explained well enough.

Would the following be correct?

$x = new Account("localhost", "root", "");

-and x would have its own connection...and then close when its done?

Just use mysql_connect() and mysql_close() at the beginning and at the end of your whole program. There is no need to instantiate a connection at every method. — ldiqual
– ldiqual, Commented Jan 2, 2012 at 23:20
@idiqual You should not be encouraging the use of mysql_ at all, particularly for somebody just coming into the language and is starting a new project. — Charles Sprayberry
– Charles Sprayberry, Commented Jan 2, 2012 at 23:23
if you want to keep db to the Accounting class connect in your __construct and implement __destruct method to destroy connection when object is destroyed. — dm03514
– dm03514, Commented Jan 2, 2012 at 23:24
Use singleton pattern. Example stackoverflow.com/questions/8685896/… — Shiplu Mokaddim
– Shiplu Mokaddim, Commented Jan 2, 2012 at 23:33

Charles Sprayberry · Accepted Answer · 2012-01-02 23:28:34Z

10

I would not advise creating your database connections this way. Create one connection and inject that into the object using it. You should not need to create a new connection for every object.

Code example:

$connection = new mysqli('localhost', 'user', 'password');

$Account = new Account($connection);

Would need to change Account to look like:

class Account {

    protected $connection;

    public function __construct(mysqli $connection) {
        $this->connection = $connection;
    }

    public function register() {
        // use $this->connection for db
    }

    public function login() {
        // use $this->connection for db
    }

}

I would also suggest that you take a look at the php.net docs about choosing a MySQL API. If you really want to use OOP with PHP and MySQL you will need to swap over to mysqli or PDO as the API you are using does not truly support an OOP interface.

edited Jan 2, 2012 at 23:28

answered Jan 2, 2012 at 23:22

Charles Sprayberry

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2 Comments

Gabriel Santos Over a year ago

You forgot to close the connection.

Charles Sprayberry Over a year ago

@GabrielSantos No, I didn't close it on purpose. What if there's another object that needs to use that connection? Then we have to open the connection again. The code that created the connection object should be responsible for closing the connection.

Gabriel Santos · Accepted Answer · 2012-01-02 23:33:17Z

3

I suggest:

public function __construct(mysqli $connection) {
    $this->connection = $connection;
    if(!$this->$connection) {
        die(mysql_error());
    }
}

public function __destruct() {
    mysql_close($this->$connection);
}

answered Jan 2, 2012 at 23:33

Gabriel Santos

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7 Comments

cmbuckley Over a year ago

I'm not sure I'd recommend using die in this (or any OO) situation.

Gabriel Santos Over a year ago

@cbuckley It is only for sample purpose.

cmbuckley Over a year ago

My only concern was that it might be a bad example to set to a beginner PHP programmer, OOP or otherwise.

Gabriel Santos Over a year ago

No, is not. die have not relation to OOP.

cmbuckley Over a year ago

Exception handling is an integral part of OOP. die() immediately produces fatal errors. See stackoverflow.com/questions/3845494/php-oop-exceptions-or-die

|

Huseyin · Accepted Answer · 2012-01-02 23:31:06Z

0

You can use some codes like as:

$db_link = mysql_connect("localhost","root","");  // Create Connection
if (!$db_link)  // Check connection 
{
  die(mysql_error());
}
mysql_select_db("db_name");
$q=mysql_query("SELECET * FROM table_name LIMIT 1");

Other queries would be here

mysql_close($db_link); // Close Connection

Creating single connection at each page is enough. more than one connection or disconnecting from sql server and loginning again may cause reduced performance.

answered Jan 2, 2012 at 23:31

Huseyin

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Comments

Community · Accepted Answer · 2017-05-23 12:06:17Z

-1

You can use a static member and all your objects will share one database connection.

See also PHP - a DB abstraction layer use static class vs singleton object?

edited May 23, 2017 at 12:06

CommunityBot

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answered Jan 2, 2012 at 23:23

Jordan

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3 Comments

PeeHaa Over a year ago

I wouldn't use neither (static class or singleton).

Charles Sprayberry Over a year ago

Downvote for singleton. No reason to introduce a database connection into the global scope with static

Gabriel Santos Over a year ago

@CharlesSprayberry Agree again.

George Reith · Accepted Answer · 2012-01-02 23:24:46Z

-1

If you wanted to shrink it and keep it neater/more manageable you could put the mysql connect code into it's own method and call it like so:

<?php
class Account
{
  private $connection;

  private function connect()
  {
    $this->$connection = mysql_connect("localhost","root","");  // Create Connection
  }

  public function register()
  {
    $this->connect();
    if (!$this->$connection)  // Check connection
    {
      die(mysql_error());
    }

    mysql_close($this->$connection); // Close Connection
  }

  public function login()
  {
    $this->connect();
    if (!$this->$connection)  // create connection
    {
      die(mysql_error());
    }
    mysql_close($this->$connection); //close connection
  }

}
?>

answered Jan 2, 2012 at 23:24

George Reith

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3 Comments

Charles Sprayberry Over a year ago

Downvoted because ultimately you're still creating the database connection every time a function is called.

Gabriel Santos Over a year ago

@CharlesSprayberry Agree with you.

George Reith Over a year ago

@CharlesSprayberry I misinterpreted the original question

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