10 days to learn the fourth day of PHP _php

Learning Purpose: Learn to connect to a database

PHP is simply a library of functions, rich in functions that make some parts of Php quite simple. We recommend that you down a PHP function manual, the total use of the.

I'll just talk about it here. Connect to MySQL database.

1, Mysql_connect

Open the MySQL server connection.
Syntax: int mysql_connect (string [hostname] [:p ort], string [username], string [password]); return value: Integer

This function establishes a connection to the MySQL server. All of these parameters can be omitted. When using this function without any arguments, the default value of the parameter hostname is localhost, the default value for the parameter username is the owner of the PHP execution itinerary, and the parameter password is an empty string (that is, no password). The parameter hostname can be followed by a colon and a port number, which represents which port to use for MySQL connection. Of course, when using the database, using Mysql_close () to turn off the connection earlier can save resources.

2, mysql_select_db

Select a database.
Syntax: int mysql_select_db (string database_name, int [link_identifier]); return value: Integer

This function selects the database in the MySQL server for subsequent data query jobs (query) processing. The success returns True, and False if it fails.

The simplest examples are:
$conn =mysql_connect ("127.0.0.1", "", "" ");
mysql_select_db ("Shop");
Connect your computer to my SQL database and open the shop database. In practical application, the point error judgment should be strengthened.

We'll talk about it today. Read the database again tomorrow.

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