PHP Database Connection With MySQL

Hello friends, this article is for php beginners who want to know how to connect to MySQL database using PHP code.

Here is your answer, I am explaining you step by step tutorial of how to make connection to MySQL database in PHP (Hypertext Preprocessor) language.

MySQL - PHP Database Connectivity

First of all you have to use mysql_connect() function. And mysql_connect() function contains host-name, username, and password.

If you have not set username then default is 'root'. If you have not set password then it is blank / empty. And hostname is 'localhost'.

Read Basic Tutorial of MySQL

Following PHP code explains how to connect with MySQL database:

$con = mysql_connect('localhost','username','password');

If you not set any username or password then write following PHP code:

$con = mysql_connect('localhost','root','');

mysql_connect() function returns a resource which is a pointer to a database connection.

After establishing connection to MySQL, now we have to select database.

To select database, we have to use mysql_select_db() function.

mysql_select_db() function takes two parameter as database name and connection to MySQL.

Consider following PHP code to select database from MySQL:

mysql_select_db('database_name', $con);

$con is a variable created above using mysql_connect() function.

After mysql_connect() and mysql_select_db() functions, now you can execute any query using mysql_query() function.

mysql_query() function takes SQL query as parameter.

mysql_query() function returns a resource that contains the results of the query called result set.

To fetch data from result set, we have to use mysql_fetch_array() function and this function takes one parameter result set.

To fetch records, we have to use while loops as illustrated in below code:

$rs = mysql_query('SELECT id, name, city FROM stud');
while( $row = mysql_fetch_array($rs) )
{
   echo $row['id'];
   echo $row['name'];
   echo $row['city'];
}

Using mysql_query() function, you can execute any query like update, delete, insert, select, etc.

What if query is not executed? You can write die() function as described below:

$rs = mysql_query('SELECT * FROM stud') or die('Query is not executed');

You can write die() function with mysql_connect(), mysql_select_db(), etc functions.

Below is a complete PHP MySQL database connectivity code:

<?php
  $con = mysql_connect('localhost','root','');
  mysql_select_db('mydb', $con);
  $rs = mysql_query('SELECT id,name,city FROM stud') or die('Query is not executed');
  while($row = mysql_fetch_array($rs))
  {
     echo $row['id'];
     echo $row['name'];
     echo $row['city'];
  }
?>

NOTE: You must have 'mydb' database in MySQL and contains one table 'stud' and table fields are 'id', 'name', 'city'. And must have some data inserted before you execute above code.