How does PHP code understand where the MySQL database is located?

Question

PHP

I want to understand how the connection between PHP and MySQL code goes. Let's say I created a config folder in it with a connection file. But how does the connection itself take place, how does the file understand that the database is on the computer?

Answer 1

The mysql database by default works through a TCP connection, port 3306. The address (host) 127.0.0.1 or localhost will be specified in the configuration file, which means that we connect to ourselves.

Answer 2

When connecting to the database, you also specify the DSN where the host, database name, login and password.
Connection example from PDO documentation

$dbh = new PDO('mysql:host=localhost;dbname=test', $user, $pass);

Connection example from the Doctrine documentation

$connectionParams = array(
    'dbname' => 'mydb',
    'user' => 'user',
    'password' => 'secret',
    'host' => 'localhost',
    'driver' => 'pdo_mysql',
);
$conn = \Doctrine\DBAL\DriverManager::getConnection($connectionParams);

Answer 3

this guide helped me. everything is perfectly shown in practice. used to transfer data from arduino with a record to the database, followed by output to a web page

Drawing Highcharts (Highstock) charts from MySQL data

unboxit.ru/blog/63-risuem-grafiki-highcharts-highs...

there are nuances in the code, but after reading the comments under the article, you can easily figure it out