可以让PHP类返回记录集

I'm trying to create a class for my access database connection and return a recordset, then iterate through the RS with MoveNext().

class AccessDBConnection 
{ 
private $db; 
private $sql; 

function __construct($db, $sql) {

    $conn = new COM('ADODB.Connection') or exit('Cannot start ADO.');
    $conn->Open("DRIVER={Microsoft Access Driver (*.mdb)}; DBQ=$db"); 

    $rs = $conn->Execute($sql);
    return $rs;

}

USE:

function testclass () {
    $rs = new AccessDBConnection("e:\database.mdb", "SELECT StudentID, UserName FROM MyTable WHERE StudentID = 'BJxxxx'");

    while (!$rs->EOF) { 
        $SID =  $rs->Fields['StudentID']->Value; 
        $UN =  $rs->Fields['UserName']->Value;
            echo $SID . " -- CLASS TEST -- " . $UN . "<br>";
                $rs->MoveNext(); 
    }
}

You can't return your resultset from constructor.

Create some separated method like getRS which will returns it.

class AccessDBConnection 
{
    private $conn;

    public function __construct($db) {

        $this->conn = new COM('ADODB.Connection') or exit('Cannot start ADO.');
        $this->conn->Open("DRIVER={Microsoft Access Driver (*.mdb)}; DBQ=$db"); 

    }

    public function query($sql) {

        return $this->conn->Execute($sql);

    }

}

Usage:

function testclass () {
    $db = new AccessDBConnection("e:\database.mdb");
    $rs = $db->query("SELECT StudentID, UserName FROM MyTable WHERE StudentID = 'BJxxxx'");

    while (!$rs->EOF) { 
        $SID =  $rs->Fields['StudentID']->Value; 
        $UN =  $rs->Fields['UserName']->Value;
            echo $SID . " -- CLASS TEST -- " . $UN . "<br>";
                $rs->MoveNext(); 
    }
}

Constructors do not return. So calling:

$rs = new AccessDBConnection($db, $sql);

Will not yield a recordset.

Some general pointers:

• Do very little in your __construct so as to make testing easier should you come to it
• Create a method akin to public function connect() which performs the connection
• Create a method for performing queries and returning a recordset.

Alternatively find an wrapper class that has already done the legwork. No sense in rewriting the wheel.