php - Is it a good practice and safe way to create user defined function with mysqli? -

am trying change project mysql mysqli. have db connection as:

$link = mysqli_connect($hostname, $username, $password, $database); if(mysqli_connect_errno()) {     echo "opps! connection not established: ", mysqli_connect_error();     exit(); } 

then have user defined function as:

function get_name($id) {     $query = mysqli_query($link, "select name staff id='$id'");     $result = mysqli_fetch_assoc($query);     return $data = $result['name']; } 

i understand have declare $link global (as shown below) work fine.

function get_name($id) {     global $link;     $query = mysqli_query($link, "select name staff id='$id'");     $result = mysqli_fetch_assoc($query);     return $data = $result['name']; } 

my question here is: practice , safe?

i wouldn't call or bad practice write function such specific purpose, fits needs. if plan exact task in multiple places throughout code, function useful make code easier read , avoid repeating yourself.

as far safety goes, need sanitize inputs before using them in query. case of integer $id field, cast integer $id = (int)$id;. other data types, want escape using $id = mysqli_real_escape_string($link, $id);. you'll safe.

i advise pdo instead of mysqli. believe it's more commonly used these days.