MySQL access classes in PHP
- by Mike
I have a connection class for MySQL that looks like this:
class MySQLConnect
{
private $connection;
private static $instances = 0;
function __construct()
{
if(MySQLConnect::$instances == 0)
{
//Connect to MySQL server
$this->connection = mysql_connect(MySQLConfig::HOST, MySQLConfig::USER, MySQLConfig::PASS)
or die("Error: Unable to connect to the MySQL Server.");
MySQLConnect::$instances = 1;
}
else
{
$msg = "Close the existing instance of the MySQLConnector class.";
die($msg);
}
}
public function singleQuery($query, $databasename)
{
mysql_select_db(MySQLConfig::DB, $this->connection)
or die("Error: Could not select database " . MySQLConfig::DB . " from the server.");
$result = mysql_query($query) or die('Query failed.');
return $result;
}
public function createResultSet($query, $databasename)
{
$rs = new MySQLResultSet($query, MySQLConfig::DB, $this->connection ) ;
return $rs;
}
public function close()
{
MySQLConnect::$instances = 0;
if(isset($this->connection) ) {
mysql_close($this->connection) ;
unset($this->connection) ;
}
}
public function __destruct()
{
$this->close();
}
}
The MySQLResultSet class looks like this:
class MySQLResultSet implements Iterator
{
private $query;
private $databasename;
private $connection;
private $result;
private $currentRow;
private $key = 0;
private $valid;
public function __construct($query, $databasename, $connection)
{
$this->query = $query;
//Select the database
$selectedDatabase = mysql_select_db($databasename, $connection)
or die("Error: Could not select database " . $this->dbname . " from the server.");
$this->result = mysql_query($this->query) or die('Query failed.');
$this->rewind();
}
public function getResult()
{
return $this->result;
}
// public function getRow()
// {
// return mysql_fetch_row($this->result);
// }
public function getNumberRows()
{
return mysql_num_rows($this->result);
}
//current() returns the current row
public function current()
{
return $this->currentRow;
}
//key() returns the current index
public function key()
{
return $this->key;
}
//next() moves forward one index
public function next()
{
if($this->currentRow = mysql_fetch_array($this->result) ) {
$this->valid = true;
$this->key++;
}else{
$this->valid = false;
}
}
//rewind() moves to the starting index
public function rewind()
{
$this->key = 0;
if(mysql_num_rows($this->result) > 0)
{
if(mysql_data_seek($this->result, 0) )
{
$this->valid = true;
$this->key = 0;
$this->currentRow = mysql_fetch_array($this->result);
}
}
else
{
$this->valid = false;
}
}
//valid returns 1 if the current position is a valid array index
//and 0 if it is not valid
public function valid()
{
return $this->valid;
}
}
The following class is an example of how I am accessing the database:
class ImageCount
{
public function getCount()
{
$mysqlConnector = new MySQLConnect();
$query = "SELECT * FROM images;";
$resultSet = $mysqlConnector->createResultSet($query, MySQLConfig::DB);
$mysqlConnector->close();
return $resultSet->getNumberRows();
}
}
I use the ImageCount class like this:
if(!ImageCount::getCount())
{
//Do something
}
Question: Is this an okay way to access the database? Could anybody recommend an alternative method if it is bad?
Thank-you.
