PHP Data Base Connection help with mysql

Question

i am new in php and want to know the code for php mysql database connection code

Answer 1

Refer to the PHP documentation for mysql_connect.

<?php

$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');

if (!$link) {
    die('Could not connect: ' . mysql_error());
}

echo 'Connected successfully';

mysql_close($link);

Answer 2

Here is the bare bone of it:

$db1 = mysql_connect( ... );
mysql_select_db('existing_db',$db1);

$db2 = mysql_connect( ... );
mysql_select_db('not_existing_db', $db2);

mysql_query(... , $db2);

More Info:

• http://php.net/manual/en/function.mysql-connect.php
• MySQL PHP Connect Tutorial

Answer 3

A Detailed Tutorial: http://www.phpf1.com/tutorial/php-mysql-tutorial.html?page=1

<?php

  mysql_connect("localhost", "username", "password") or die(mysql_error());
  echo "Connection to the server was successful!<br/>";

  mysql_select_db("test") or die(mysql_error());
  echo "Database was selected!<br/>";

?>

Answer 4

Watch also mysqli,it's the "new way" of connecting to mysql http://php.net/manual/en/book.mysqli.php it has more functions and there are rumors that in php6 mysql will be deprecated for the mysqli implementation. you can use it as an object(but if you're new also to OO it may be a little more difficult to understand)like this:

//--connection to the database--
$db=mysqli_connect('sql.mysqlhost.com','database_username','password','database_name');//you can also use $db=new mysqli(....) but mysql_connect does the same thing and it's more cler on what it's doing
//--a simple query--
if($result=$db::query('SELECT name,value FROM mytable')){//query ok
    echo 'Select returned ',$result->num_rows,'rows<br/>';
    while($row=$result->fetch_assoc()){//get one row in an assoc.array
            echo 'Name:',$row['name'],' Value:',$row['value'],'<br/>';//print each row
    }
    $result->close();
}
else//query error
 die('MYSQL ERROR:'.$db->error);

or with functions like in mysql

//--connection to the database--
$db=mysqli_connect('sql.mysqlhost.com','database_username','password','database_name');
//--a simple query--
if($result=mysql_query($db,'SELECT name,value FROM mytable')){//query ok
    echo 'Select returned ',mysql_num_rows($result),'rows<br/>';
    while($row=mysqli_fetch_assoc($result)){//get one row in an assoc.array
            echo 'Name:',$row['name'],' Value:',$row['value'],'<br/>';//print each row
    }
    mysql_free_result($result);
}
else//query error
 die('MYSQL ERROR:'.mysqli_connect_error());

You can also use a persistent mysql connection prepending 'p:' to the sql host,for example if your host is sql.myhost.com:

$db=mysqli_connect('p:sql.mysqlhost.com','database_username','password','database_name');

Using a persistent connection should give you a great performance boost and mysqli should handle the persistent connection a lot better than the normal mysql extension.

Remember to sanitize the input of your query to avoid SQL INJECTION,you can do like this:

$result=mysql_query($db,"SELECT name,value FROM mytable where name='".mysqli_real_escape_string($input_name)."'");

or using a prepared statement that's a little more complicated and it's better only if you repeat the same command multiple times only changing the input data.