Solution Review: PHP Database

<?php

// DB credentials.
define('DB_HOST', '127.0.0.1'); 
define('DB_USER', 'educative');//database username 
define('DB_PASS', 'root');// database passord 
define('DB_NAME', 'testing'); //database name

class Db {
    // Hold the handle for the PDO object in a private variable. 
    private $dbh;
    // Establish database connection 
    // or display an error message. 
    function __construct()
    {
        try {
            $this->dbh = new \PDO("mysql:host=".DB_HOST.";dbname=".DB_NAME, DB_USER, DB_PASS,
            array(PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES 'utf8'"));

            echo "connected\n";
        }
        catch (PDOException $e) {
            exit("Error: " . $e->getMessage()); 
        }
    }

    // Method to get the database handler
    // so it can be used outside of this class. 
    function get()
    {
        return $this->dbh; 
    }
    
     // Set the PDO object to null to close the connection.
    function close(){
        $this->dbh = null;
    } 
}
class User {
    private $tableName = 'users'; 
    private $dbCon;

    // First, save the connection in a private property.
    function __construct($dbCon) {
        $this->dbCon = $dbCon;

        // Creating table "users" in database

        $sql = "CREATE TABLE IF NOT EXISTS users (
        id int(10) UNSIGNED NOT NULL AUTO_INCREMENT, 
        name varchar(60) DEFAULT NULL,
        phone varchar(14) DEFAULT NULL,
        city varchar(60) DEFAULT NULL,
        date_added date DEFAULT NULL,
        PRIMARY KEY (id)
        )";

        // use exec() because no results are returned

        $this->dbCon->exec($sql);
        echo "Table users created successfully\n";
    }

    // Insert new user to the database.
    function insert($name,$phone,$city) {
        // The insert query.
        $sql = "INSERT INTO `{$this->tableName}` (`name`,`phone`, `city`, `date_added`)
        VALUES
        (:name,:phone,:city,:created)";
        
        // Bind and filter.
        $query = $this->dbCon->prepare($sql);

        $query->bindParam(':name',$name,PDO::PARAM_STR);
        $query->bindParam(':phone',$phone,PDO::PARAM_STR);
        $query->bindParam(':city',$city,PDO::PARAM_STR);
        
        $now = date('Y-m-d');
        $query->bindParam(':created',$now,PDO::PARAM_STR);

        $query -> execute();
        // The id of the newly created row in the table.
        $lastInsertId = $this->dbCon->lastInsertId();

        if($lastInsertId>0) 
            return $lastInsertId;
        else
            return false;
    }

    function getUserById($id) {
        $sql = "SELECT * FROM `{$this->tableName}` WHERE `id` = :id LIMIT 1"; 
        $query = $this->dbCon->prepare($sql);

        $query -> bindParam(':id', $id, PDO::PARAM_INT);
        $query -> execute();
        $results = $query -> fetchAll(PDO::FETCH_OBJ); 

        if($query -> rowCount() < 1) 
            return false;
        return $results[0]; 
    }

    // Get all the users.
    function getAll() {
        $sql = "SELECT * FROM `{$this->tableName}` WHERE 1"; 
        $query = $this->dbCon->prepare($sql);

        $query -> bindParam(':id', $id, PDO::PARAM_INT); 
        $query -> execute();
        $results = $query -> fetchAll(PDO::FETCH_OBJ); 

        if($query -> rowCount() < 1) 
            return false;

        return $results; 
    }

    function updateUser($id,$array) {
        $sql = "UPDATE `{$this->tableName}` SET ";
        $columns = array();
        
        foreach($array as $fieldName => $value) {
            $columns[] = "`{$fieldName}` = :{$fieldName}"; 
        }
        $sql .= implode(',',$columns);
        $sql .= ' WHERE `id` = :id';
        $query = $this->dbCon->prepare($sql);

        foreach($array as $fieldName => $value) {
            // Use bindValue, not bindParam because
            // bindParam only gets its value at the time of execution. 
            $query -> bindValue(":{$fieldName}",$value);
        }
        $query -> bindParam(':id', $id, PDO::PARAM_INT);

        $query -> execute();
        if($query -> rowCount() < 1) 
            return false;
        
        return $id; 
    }

    function delete($id) {
        $sql = "DELETE FROM `{$this->tableName}` WHERE `id`=:id"; 
        $query = $this->dbCon->prepare($sql);
        $query -> bindParam(':id', $id, PDO::PARAM_INT);
        $query -> execute();
        if($query -> rowCount() < 1) 
            return false;
        return true; 
    }
}

// Create the pdo object.
$db = new Db;

// Get the connection.
$dbCon   = $db->get();

// When creating the new User class 
// pass the connection.
$userObj = new User($dbCon);

// Test insertion.
echo "Inserting user in table\n";
var_dump($userObj->insert('James Tiberius Kirk','0544308209','Riverside, Iowa'));
    
// Test selection.
echo "\nGetting user by id\n";
var_dump($userObj->getUserById(1));

echo "\nGetting all users the table\n";
var_dump($userObj->getAll());
 
// Test update.
echo "\nUpdated the user\n";
$array=['name'=>'Captain Kirk','city'=>'Tarsus IV','date_added'=>'2233-03-22'];
var_dump($userObj->updateUser(1,$array));
var_dump($userObj->getUserById(1));

// Test delete.
echo "\nDeleted the user\n";
var_dump($userObj->delete(1));