To retrieve and manipulate the data from MySQL database server.

This function requires four parameters to connect to database server.

INSERT, SELECT,UPDATE and DELETE.

Relational Database Management System.

1. The mysqli_affected_rows() function returns the number of affected rows in the previous SELECT, INSERT, UPDATE, REPLACE,or DELETE query.
2. Syntax
mysqli_affected_rows( connection);

1.The mysqli_connect_error() function returns the error description from the last connection error, if any.
2.Syntax
mysqli_connect_error( );

The SQL query statements are helping with PHP MySQL extension to achieve the objective of MySQL and PHP connection.

The main goal of MySQL and PHP connectivity is to retrieve and manipulate the data from MySQL database server.

(i) MySQL is the most popular Open Source Relational SQL Database Management System.
(ii) MySQL is one of the best RDBMS being used for developing various web-based software applications.

Database Connections: Accessing MySQL Database, connect to Database Server machine via PHP scripting language using Mysqli_connect() Function.
Syntax:
mysqli_connect("Server Name","User Name","Password","DB Name");
This function requires four parameters to connect to database server. Database Server name, Database username, password and Database Name.

Syntax:
mysqli_connect("Server Name","User Name","password","DB Name");
Example:

mysqli_affected rows( )	mysqli_fetch_assoc( )
It returns the number of affected rows in the prearvious SELECT, INSERT  UPDATE, REPLACE, or DELETE query.	It fetches a result rowas an associative aray
Return value: An integer >0 indicates the  number of rows affected (0 indicates that no records were affected. '-1' indicates that the query returned an error).	Returns an associative array of strings representing the fetched row. NULL if there are no more rows in result set.
Syntax: mysqli_affected_rows (connection);	Syntax: mysqli fetch_as-soc(result);

(i) Four Parameters are used to connect to the Database server.
(ii) They are
1.＄ servername -> Database Server server IP address
2.＄ susername -> Database Server User Name
3.＄ password -> Database Server Password
4.＄ DB_Name -> Database Name

Database Connections: Before accessing MYSQL Database, connect to Database Server machine via PHP scripting language using Mysqli_connect() Function.
Syntax:
mysqli_connect(“Server Name”,“User Name”,“Password”,“DB Name”);
This function requires four parameters to connect to database server. Database Server name, Database username, password and Database Name.
Managing Database Connections: The below code describes managing database connection methods and features.
<?php
$servername = “localhost”;
$username = “username”;
$password = “password”;
SDB_name = “School_DB”;
$conn = mysqli_connect($servername, $username, $password,$DB_name);
if(!$conn){
die(“Connection failed: “ . mysqli_connect_error( ));
}
echo “Connected successfully”;
?>
In the above code snippet, four variables are used to connect to the Database server. They are

The mysqli_connect function uses these variables and connect Database server to PHP. If connection gets fail, output will be printed with MySQL error code. Otherwise connection is success.

MySQL function in PHP:
In PHP Scripting language many functions are available for MySQL Database connectivity and executing SQL queries.
MySQLi is extension in PHP scripting language which gives access to the MYSQL database. MySQLi extension was introduced version 5.0.0,
The MySQLi extension contains the following important functions which are related to MySQL database connectivity and management.
i) Mysqli_connect() Function
ii) Mysqli_close() Function
iii) Mysqli_query() Function
(i) Database Connections:
Before accessing MySQL Database, connect to Database Server machine via PHP scripting language using Mysqli_connect() Function.
Syntax :
mysqli_connect("Server Name "User Name","Password"DB Name");
This function requires four parameters to connect to database server. Database Server name, Database username, password anda Database Name.
(ii) Managing Database Connections :
The below code describes managing database connection methods and features.

The mysqli_connect function uses these variables to connect Database server to PHP. If connection gets fail, output will be printed with MySQL error code. Otherwise connection is success.
(iii) Performing Queries :
The main goal of MySQL and PHP connectivity is to retrieve and manipulate the data from MYSQL database server. The SQL query statements help in PHP MySQL extension to achieve the objective of MYSQL and PHP connection. "mysqli_query" is a function, that helps to execute the SQL query statements in PHP scripting language.
Syntax:
mysqli_query("Connection Object","SQL Query")
Example:

Closing Connection :
mysqli_close() Function is used to close an existing opened database connection between PHP scripting and MySQL Database Server.