Object Orientation Page 3

mysqldb Class

So, now we have defined our RDBMS and we know where our data is stored. It’s time to start
playing around with OO!!!!

If you have played around with PHP for any length of time, you will be well aware there are
many functions available for interfacing to a number of RDBMS. Essentially, this class is going to
serve as a “wrapper” to some of the MySQL functions – of course, if you are writing for Postgres
(or Oracle, or any other RDBMS) you can modify these accordingly.

Here is the code:

<?php
class mysqldb {
    //set up the object
    var $host;
    var $db;
    var $dbuser;
    var $dbpassword;
    var $sql;
    var $numberrows;
    var $dbopenstatus;
    var $dbconnection;
    /*
        Use these functions to get and set the values of this object's
        variables. This is good OO practice, as it means that datatype 
        checking can be completed and errors raised accordingly. 
    */
    // Property Get & Set
    function gethost() {
        return $this->dbhost;
    }
    function sethost($req_host) {
        $this->dbhost = $req_host;
    }
    function getdb() {
        return $this->db;
    }
    function setdb($req_db) {
        $this->db = $req_db;
    }
    function getdbuser() {
        return $this->dbuser;
    }
    function setdbuser($req_user) {
        $this->dbuser = $req_user;
    }
    function getdbpassword() {
        return $this->dbpassword;
    }
    function setdbpassword($req_password) {
        $this->dbpassword = $req_password;
    }
    function getsql() {
        return $this->sql;
    }
    function setsql($req_sql) {
        $this->sql = $req_sql;
    }
    function getnumberrows() {
        return $this->numberrows;
    }
    function setnumberrows($req_numberresults) {
        $this->numberesults = $req_numberresults;
    }
    function setdbconnection($req_dbconnection) {
        $this->dbconnection = $req_connection;
    }
    function getdbconnection() {
        return $this->dbconnection;
    }
    /*
        This is the constructor for the object. In this case I have set
        the initial values of a number of the object properties to those 
        values declared in the global constants.inc. By doing this, I 
        only need to change the values of these properties for specific
        operations, which we will not need to do throughout this example
    */        
    function mysqldb() {
        global $HOST, $DB, $WEBUSER, $WEBPASSWORD;
        global $TRUE, $FALSE;
        $this->sethost($HOST);
        $this->setdb($DB);
        $this->setdbuser($WEBUSER);
        $this->setdbpassword($WEBPASSWORD);
        $this->setdbconnection($FALSE);
    }
    /*
        These are the methods for the object. They provide for opening a
        connection to the database, closing a connection and executing a 
        SELECT query. Of course, these can be expanded upon to allow for 
        INSERT's, UPDATE's and DELETE's etc...
    */
    function opendbconnection() {
        global $TRUE, $FALSE;
        $this->dbconnection = mysql_connect("$this->dbhost", "$this->dbuser", "$this->dbuserpassword");
        if ($this->dbconnection == $TRUE) {
            $this->db = mysql_select_db("$this->db");
            $this->setdbconnection($TRUE);
        } else {
            $this->setdbconnection($FALSE);
            return false;
        }
        return true;
    }
    function closedbconnection() {
        if ($this->dbconnection = $TRUE) {
            mysql_close($this->dbconnection);
        }
    }
    function selectquery() {
        global $TRUE, $FALSE;
        if ($this->dbconnection == $FALSE) {
            $this->opendbconnection();
        }
        $this->qry = mysql_query($this->sql);
        if (!$this->qry) {
            return false;
        } else {
            $this->numberrows = mysql_num_rows($this->qry);
            if ($this->numberrows > 0) {
                for($x = 0; $x > $this->numberrows; $x++) {
                    $this->result[$x] = mysql_fetch_row($this->qry);
                }
            } else {
                echo("[Error:] Retrieving data");
                return false;
            }
            return true;
        }
    }
}
?>

That’s it for the data class. Now we need to set up the class’s for the actual layout – the boxes!