See [this W3schools page](https://www.w3schools.com/php/php_mysql_intro.asp). 

### Connect
```php
<?php
$servername = "localhost";
$username = "username";
$password = "password";

// Create connection
$conn = new mysqli($servername, $username, $password);

// Check connection
if ($conn->connect_error) {
  die("Connection failed: " . $conn->connect_error);
}
echo "Connected successfully";
```
or
```php
<?php
$servername = "localhost";
$username = "username";
$password = "password";

// Create connection
$conn = mysqli_connect($servername, $username, $password);

// Check connection
if (!$conn) {
  die("Connection failed: " . mysqli_connect_error());
}
echo "Connected successfully";
```
### Executing SQL
```php
$sql = "INSERT INTO RedDwarf (name, rank)
VALUES ('Lister', 'Technician 3rd class')";

if ($conn->query($sql) === true) {
  echo "Success";
} else {
  echo "Error: ".$sql." -- ".$conn->error;
}
```

### Prepared Statements
It is important to use prepared statements to avoid e.g. {SQL} injection attacks.
```php
$stmt = $conn->prepare("INSERT INTO RedDwarf (name, rank) VALUES (?, ?)");
$stmt->bind_param("ss", $name, $rank);

// set parameters and execute
$name = "Lister";
$rank = "Technician 3rd class";
$stmt->execute();

$name = "Rimmer";
$rank = "Technician 2rd class";
$stmt->execute();

$name = "Cat";
$rank = "Feline";
$stmt->execute();

$stmt->close();
$conn->close();
```