Generating Outputs from MySQL with Static Members and Methods in PHP 5 - Working with MySQL
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Before I proceed to demonstrate how to use static methods for generating different outputs from a given MySQL database table, first I need to create a pair of classes that allow me to interact with the database server. Taking this into account, I listed the signature for these two classes below:
// define 'MySQL' class
class MySQL{
private $conId;
private $host;
private $user;
private $password;
private $database;
private $result;
public function
__construct($options=array()){
if(count($options)<4){
throw new Exception('Invalid number of connection
parameters');}
foreach($options as $parameter=>$value){
if(!$value){
throw new Exception
('Invalid parameter '.$parameter);}
$this->{$parameter}=$value;}
$this->connectDB();}
private function
connectDB(){
if(!$this->conId=mysql_connect($this->host,$this->user,
$this->password)){
throw new Exception('Error connecting to the server');}
if(!mysql_select_db($this->database,$this->conId)){
throw new Exception('Error selecting
database');}
}
public function
query($query){
if(!$this->result=mysql_query($query,$this->conId)){
throw new Exception('Error performing query '.$query);}
return new Result($this,$this->result);}
}
// define 'Result' class
class Result{
private $mysql;
private $result;
public function
__construct(&$mysql,$result){
$this->mysql=&$mysql;
$this->result=$result;}
public function
fetchRow(){
return mysql_fetch_assoc($this->result);
}
public function
countRows(){
if(!$rows=mysql_num_rows($this->result)){
throw new Exception('Error counting rows');
}
return $rows; }
public function
countAffectedRows(){
if(!$rows=mysql_affected_rows($this->mysql->conId)){
throw new Exception('Error counting affected rows');}
return $rows;}
public function
getInsertID(){
if(!$id=mysql_insert_id($this->mysql->conId)){
throw new Exception('Error getting ID');}
return $id;}
public function
seekRow($row=0){
if(!int($row)||$row<0){
throw new Exception('Invalid result set offset');}
if(!mysql_data_seek($this->result,$row)){
throw new Exception('Error seeking data');}
}
public function
fetchFormattedResult($query,$closeTag='</p>'){
if(preg_match("/^SELECT/",$query)){
throw new Exception('Query must begin with SELECT');}
$output='';
$opentag=str_replace('/','',$endTag);
while($row=$this->fetchRow()){
$output.=$openTag.$row.$closeTag;}
unset($openTag,$closeTag);
return $output;
}
public function
getResultSet(){
return $this->result;
}
}
In simple words, the above pair of classes will allow me to perform some useful tasks, like connecting to MySQL, running queries, handling data sets, and so forth, which is very convenient for generating different outputs from one or many database tables. However, definitely these classes aren’t the main subject of this article, therefore I don’t want you to get bored quickly reading my explanations about what they do.
Instead, now that the classes have been defined, let’s move on to the following section and learn more on how to create a few more understandable classes, where each of them will be responsible for generating different outputs from some MySQL database tables. And don’t you worry, because static methods are just around the corner, trust me!
In order to see how these brand new classes will be defined, please click on the link below and keep reading.
Next: Creating the ResultToString, ResultToXML and ResultToArray classes >>
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