Smartest way to access database with sql via functions in php - php

Question

I'm making a small CMS for some fun and practice. And I've come across this problem where I have to access a database multiple times in different functions. And the way I do it now by making a new prepared statement with the code and all to access the database in the function doesn't seem very convenient since the code is very repetitive and I'm using mostly the same code for each function. So how would I go about creating a class maybe or some functions that reduce the amount of code used in the functions that gather the information from that database? I currently use the following queries in SQL
SELECT
UPDATE
INSERT
DELETE
So mostly the basic ones. The code I'm using is basic PHP code where I'm using prepared statements to access my database like this:
// Create database connection
$con = db_connect();
// Initialize $error variable for errors
$error = "";
if ($stmt = $con->prepare("SELECT * FROM profiles WHERE username = ?")) {
// Bind the $username variable to the parameter in the query
$stmt->bind_param('s', $username);
// Execute the prepared query
$stmt->execute();
$stmt->store_result();
// Assign the data recieved from the database (if any)
$stmt->bind_result($data);
$stmt->fetch();
if ($stmt->num_rows == 1) {
if (!empty($stmt->error)) {
printf("Error: %s.\n", $stmt->error);
return false;
}
// Query successful
} else {
$error .= "User doesn't exist";
return false;
}
} else {
$error .= 'Could not connect to database';
return false;
}
To me this seems like pretty easy to use code, but when you have to paste it again and again in different functions, then it gets a bit frustrating.

Answer 1

You should use Dependency Injection.
By injecting the Database connection into a Profile's class, you have much more maneuverability to do what you please.
You can change that database to whatever you want (MongoDB, Cassandra, MySQL).
You are only declaring the connection once; which performs better and faster
Makes it easier to test and develop (echo & print_r & unit testing)
Handel exceptions in 1 place
Database is loosely couple with rest of code.
ex:
class Profile {
private $db = null;
public function __construct($db Database) {
$this->db = $db;
}
public function getProfile() {
//ish....
$this->db->query("SELECT * FROM profiles WHERE username = ?");
}
public function insert() {
...
}
public function update() {
...
}
public function delete() {
...
}
}
To access the database, I would do something like this and also implement what you have (prepared statements are great!):
class Database {
private $conn = null;
public function __construct($db Database) {
$this->conn = new PDO('mysql:host=localhost;dbname=myDatabase', $username, $password);
$this->conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
return $this->conn;
}
public function query($sql) {
try {
return $conn->query($sql);
} catch (Exception $e) {
echo $e->getMessage();
}
}
}
A very good explaination and tutorial can be found here: http://code.tutsplus.com/tutorials/dependency-injection-huh--net-26903