MySQL is a freely available open source Relational Database Management System (RDBMS) that uses Structured Query Language (SQL). A database consists of one or more tables. You can access MySQL databases directly through PHP scripts. When you create a new database, you must only specify the first three arguments to the mysqli object (servername, username and password).
PHP uses mysqli_query function to create or delete a MySQL database. This function takes two parameters and returns TRUE on success or FALSE on failure.
<?php
$servername ="localhost";
$username ="yourusername";
$password= "yourpassword";
// Creating a connection
$conn = new mysqli($servername, $username, $password);
// Check connection
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
// Creating a database named DEMO
$sql = "Create database DEMO";
if ($conn->query($sql) === TRUE) {
echo "Database DEMO created successfully";
} else {
echo "Error creating database: " . $conn->error;
}
// closing connection
$conn->close();
?>
PHP provides mysqli_connect() function to open a database connection. This function takes five parameters and returns a MySQL link identifier on success or FALSE on failure.
<?php
$servername = "localhost";
$username = "your username";
$password = "your password";
$database = "demo";
// Create connection
$conn = mysqli_connect($servername, $username, $password, $database);
// Check connection
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
echo "Database DEMO successfully connected";
mysqli_close($conn);
?>
<?php
$host ="localhost";
$user ="yourusername";
$pass="yourpassword";
$database1 ="demo1";
$database2 ="demo2";
$dbh1 = new mysqli($host, $user, $pass, $database1);
if($dbh1->connect_errno > 0){
die("Unable to connect to database" . $dbh1->connect_error);
}else{
echo "Database demo1 is connected.";
}
$dbh2 = new mysqli($host, $user, $pass, $database2);
if($dbh2->connect_errno > 0){
die("Unable to connect to database" . $dbh2->connect_error);
}else{
echo "Database demo2 is connected.";
}
?>
<?php
$server = "localhost";
$dbuser = "yourusername";
$dbpass = "yourpassword";
$dbh = new PDO( "mysql:host=$server", $dbuser, $dbpass );
$dbs = $dbh->query( "SHOW DATABASES" );
while( ( $db = $dbs->fetchColumn( 0 ) ) !== false )
{
echo $db."<br>";
}
?>
<?php
$link = mysqli_connect("localhost", "yourusername", "yourpassword");
if($link === false){
die("ERROR: Could not connect. " . mysqli_connect_error());
}
$sql = "DROP database DEMO";
if(mysqli_query($link, $sql)){
echo "Database DEMO deleted successfully.";
}
else{
echo "ERROR: Could not able to execute $sql. "
. mysqli_error($link);
}
mysqli_close($link);
?>