如果其中之一未连接，如何在2个mysql数据库之间切换？

Question

I have 2 database servers DRC and Production server..

I connected php config file with the Production server ip to connect its database (it is working fine), and i made an if statement if production database is not connected, not selected or dropped then go and connect with the DRC server to get its database.

the code below make this action it is working fine for switching 2 databases on local host but it is not connecting to the DRC database if the Production one is not available.

//Production constants
defined ('DB_SERVER')? null : define ("DB_SERVER" , "20.20.10.1");
defined ('DB_USER') ? null : define ("DB_USER" , "root");
defined ('DB_PASS') ? null : define ("DB_PASS" , "rootpass");
defined ('DB_NAME') ? null : define ("DB_NAME" , "dbname");

//DRC constants
defined ('DB_SERVER_DRC')? null : define ("DB_SERVER_DRC" , "20.20.10.2");
defined ('DB_USER_DRC') ? null : define ("DB_USER_DRC" , "root");
defined ('DB_PASS_DRC') ? null : define ("DB_PASS_DRC" , "rootpass");
defined ('DB_NAME_DRC') ? null : define ("DB_NAME_DRC" , "dbname");


function __construct() {
    $this->open_connection();
}

public function open_connection() {
    $this->connection = mysql_connect(DB_SERVER, DB_USER, DB_PASS);
    if (!$this->connection) {
        $this->open_connection_DRC();
    } else {
        $db_select = mysql_select_db(DB_NAME, $this->connection);
        if (!$db_select) {
            $this->open_connection_DRC();
        }
    }
}

public function open_connection_DRC() {
    $this->connection = mysql_connect(DB_SERVER_DRC, DB_USER_DRC, DB_PASS_DRC);
    if (!$this->connection) {
        die("Database connection failed: " . mysql_error());
    } else {
        $db_select = mysql_select_db(DB_NAME_DRC, $this->connection);
        if (!$db_select) {
            die("Database selection failed: " . mysql_error());
        }
    }
}

Any solution or other way to do that, Waiting for your positive response guys.

Answer 1

mysql_connect - Returns a MySQL link identifier on success or FALSE on failure. That's what you can do according to my knowledge. if it returns false connect to the other database.

Answer 2

Can you try with below change in open_connection_DRC function, as per PHP manual you need to pass 5th Boolean argument $new_link as true, when you are trying to open multiple connections.

I am assuming here, that you are connected to production sever and database is not there on production server, so you are trying to open new mysql connection to DRC server.

public function open_connection_DRC() {
    $this->connection = mysql_connect(DB_SERVER_DRC, DB_USER_DRC, DB_PASS_DRC, true);

Also it is better to unset $this->connection once you found out that DB is not present on production server.