php pdo automatic paging code and examples

/**
* Class name: PdoPage
* Author: Xie Shengtao shishengsoft@gmail.com
* Description: Inherited from the PDO class, it adds automatic paging function, similar to the automatic paging function of MS ADO components.
*/ bbs.it-home.org
//-------------Start-------- -------
class PdoPage extends PDO {
public $RecordCount = 0; // Total number of records in the recordset
public $AutoPage = false;// Enable automatic paging
public $PageSize = 0;// Each Number of record rows in the page
public $CurrentPage = 0; // Current page
public $Pages = 0; // Total number of pages
public $BOF = false; // Before the cursor reaches the record set
public $EOF = false; / / After the cursor reaches the record set
private $RecordSet = null; // Record set
private $mCurrentRow = -1; // Current cursor position in the record set
private $Rows = 0; //Total number of records
// Close the connection
 public function Close(){unset($this);}
//Paging query
public function QueryEx($SqlString){
//Whether the automatic paging function is enabled
if($this->AutoPage){
//Check PageSize parameter
if ($this->PageSize <=0) die("Warning: PageSize cannot be negative or zero.");
// Calculate the total number of records
$rs = @parent::query($this ->rebuildSqlString($SqlString));
$this->Rows = $rs->fetchColumn();
// Calculate the total number of pages
if ($this->Rows < $this-> PageSize) {$this->Pages = 1;}
elseif ($this->Rows % $this->PageSize) {$this->Pages = intval($this->Rows/$this- >PageSize)+1;}
else {$this->Pages = intval($this->Rows/$this->PageSize);}
// Constrain the CurrentPage value so that it is between 1 and Pages between.
if($this->CurrentPage < 1) {$this->CurrentPage =1;}
if($this->CurrentPage > $this->Pages) {$this->CurrentPage = $this->Pages;}
//Calculate the offset
$Offset = $this->PageSize * ($this->CurrentPage - 1);
//Reorganize the SQL statement, remove the semicolon in SqlString
$SqlString = str_replace(";","",$SqlString) . " LIMIT $Offset,$this->PageSize;";
}
// Query and return the record set
$rs = new PDOStatement();
$rs = @parent::query($SqlString);
$this->RecordSet = $rs->fetchAll();//returns an array.
$this->RecordCount = count($this- >RecordSet);
if(!$this->AutoPage){$this->Pages = (!$this->RecordCount)?0:1;}
return $this->RecordCount;
}
// Get the field value
public function FieldValue($FieldName=""){
return ($this->RecordSet[$this->mCurrentRow][$FieldName]);
}
//---- ----Move record set cursor---------------
public function Move($RowPos){
if ($RowPos<0) $RowPos = 0;
if ($RowPos > $this->RecordCount-1) $RowPos = $this->RecordCount-1;
$this->mCurrentRow = $RowPos;
$this->EOF = false;
$this-> BOF = false;
}
public function MoveNext(){
if($this->mCurrentRow < $this->RecordCount-1){
$this->mCurrentRow++;
$this->EOF = false;
$this->BOF = false;
}
else{
$this->EOF = true;
}
}
public function MovePrev(){
if($this->mCurrentRow > 0 ){
$this->mCurrentRow--;
$this->EOF = false;
$this->BOF = false;
}else{
$this->BOF = true;
}
}
public function MoveFirst(){
$this->mCurrentRow = 0;
$this->EOF = false;
$this->BOF = false;
}
public function MoveLast(){
$this- >mCurrentRow = $this->RecordCount-1;
$this->EOF = false;
$this->BOF = false;
}
//------------ -------------------------------------
// Used to perform insertion, modification, deletion, etc. Operation
public function Execute($SqlString){
return @parent::query($SqlString);
}
//-----------------Private function---- --------------------------
// Reconstruct the SQL statement, such as rewriting "select * from tb2" to "select count(*) from tb2", designed to improve query efficiency.
private function rebuildSqlString($SqlString){
if(preg_match("/select[ ,./w+/*]+ from/",$SqlString,$marr)){
$columns = preg_replace("/select|from/ ","",$marr[0]);
$columns = preg_replace("//*/","/*",$columns);
$result = preg_replace("/$columns/"," count( *) ",$SqlString);
return $result;
}
}
//----------------End---------------- ------------------
}
//-------------End------------ -----------------------
?>

2. Usage examples: It is necessary to modify the MySQL user name, password, database name and other information.

include_once("./pdopage_class.php");
$db = new PdoPage("mysql:host=localhost;dbname=mydb","root"," 123456");
$db->Execute("set character set gbk;");
$db->AutoPage = false;
$db->PageSize = 6;
$db->CurrentPage = 1 ;
$db->QueryEx("select * from tb2;");
$db->MoveFirst();
while (!$db->EOF) {
echo $db->FieldValue(" id"),"/t",$db->FieldValue("name"),"/t",$db->FieldValue("age"),"/n";
$db->MoveNext ();
}
$db->Close();
?>