如何使用类和函数oops概念在php中获取数据库

Question

我是php的新开发人员。我在下面编写一个类和函数来连接到数据库。但是代码不起作用如何创建类和函数 OOPS 概念帮助我。

法典：

class database {
#code
var $host = "localhost";
var $username ="root";
var $password ="";
var $dbase ="blue";
var $myconnect;
function connectTodata()
{
    $conn = mysql_connect($this->host, $this->username, $this->password);
    if(!$conn)
    {
        die("Cannot Connect to the datagase");
    }
    else
    {
        $his->myconnect = $conn;
        echo "Connect Established";
    }
    return $myconnect;
}
 function selectDatabase() // selecting the database.
{
    mysql_select_db($this->database);  //use php inbuild functions for select database
    if(mysql_error()) // if error occured display the error message
    {
        echo "Cannot find the database ".$this->database;
    }
     echo "Database selected..";       
}
function closeConnection() // close the connection
{
    mysql_close($this->myconn);
    echo "Connection closed";
   }
}

Answer 1

只是为了让它工作：

class database 
{
    #code
    var $host = "localhost";
    var $username ="root";
    var $password ="";
    var $dbase ="blue";
    var $myconnect;
    function connectTodata()
    {
        $this->myconnect = mysql_connect($this->host, $this->username, $this->password);
        if(!$this->myconnect) die("Cannot Connect to the datagase");
        echo "Connect Established";
        return $this->myconnect;
    }
    function selectDatabase() // selecting the database.
    {
        mysql_select_db($this->database);  //use php inbuild functions for select database
        if(mysql_error()) // if error occured display the error message
        {
            echo "Cannot find the database ".$this->database;
        }
     echo "Database selected..";       
    }
    function closeConnection() // close the connection
    {
        mysql_close($this->myconnect);
        echo "Connection closed";
    }
}

Answer 2

按照前面的海报所述修复错误，然后尝试开始：

$database_connection=new database();
$database_handle=$database_connection->connectTodata();
$database_connection->selectDatabase();
$database_connection->closeConnection();
unset($database_connection);
exit();

在代码块之间的空间中，您可以添加MySQL查询并使用$database_handle作为第二个参数。

Answer 3

你可以

使用构造函数，这样你就不需要每次都调用类函数：

 class database {
    var $host = "localhost";
    var $username ="root";
    var $password ="";
    var $dbase ="blue";
    var $myconnect;
    function __construct()  {
        $this->myconnect = mysql_connect($this->host, $this->username, $this->password);
       if( !$this->myconnect )  {
            $msg  = "could not connect to mysql database <Br/>";
            $msg .= mysql_error();
            die($msg);
        }
        $db_connect = mysql_select_db($this->dbase, $this->myconnect);
        if( !$db_connect )  {
            die(" can not select database n".mysql_error());
        }
    }
    function __destruct() {
        mysql_close($this->myconnect);
    }
}
// call database 
$con = new database();

Answer 4

您可以借助以下功能来

定义它们

define("DB_SERVER_NAME","your host");
define("DB_USER_NAME","your user name");
define("DB_USER_PASSWORD","your password");
define("DB_DATABASE_NAME","your database");

现在连接文件：

class DBClass{
public $DB_LINK;
public $DB_DATABASE_NAME;
function DBClass($Main_DB = FALSE){
$this->DB_LINK = @mysqli_connect(DB_SERVER_NAME,DB_USER_NAME,DB_USER_PASSWORD,DB_DATABASE_NAME);
if(! $this->DB_LINK){
die("<h2>Could not connect to Database.</h2>");
}
}
function __destruct(){
mysqli_close($this->DB_LINK);
}   
}

这对我来说非常有效