DatabaseTable.php

<?php
namespace Ninja;
class DatabaseTable
{
     private $pdo;
        private $table;
        private $primaryKey;
        private $className;
        private $constructorArgs;

        public function __construct(\PDO $pdo, string $table,
        string $primaryKey, string $className = '\stdClass',
        array $constructorArgs = []) {
        $this->pdo = $pdo;
        $this->table = $table;
        $this->primaryKey = $primaryKey;
        $this->className = $className;
        $this->constructorArgs = $constructorArgs;
        }

private function query($sql, $parameters = []) {
$query = $this->pdo->prepare($sql);
$query->execute($parameters);
return $query;
}

public function total() {
$query = $this->query('SELECT COUNT(*)
FROM `' . $this->table . '`');
$row = $query->fetch();
return $row[0];
}

   // TRY TO UNDERSTAND findById function better. Check previous version
public function findById($value) {
$query = 'SELECT * FROM `' . $this->table . '` WHERE `' .
$this->primaryKey . '` = :value';
$parameters = [
'value' => $value
];
$query = $this->query($query, $parameters);
return $query->fetchObject($this->className,
$this->constructorArgs);
}

public function findAll() {
    $result = $this->query('SELECT *
FROM ' . $this->table);
    //return $result->fetchAll();
    return $result->fetchAll(\PDO::FETCH_CLASS, $this->className, $this->constructorArgs);
}

public function find($column, $value) {
    $query = 'SELECT * FROM `' . $this->table . '` WHERE
        `' . $column . '` = :value';
    $parameters = [
        'value' => $value
    ];
    $query = $this->query($query, $parameters);
    return $query->fetchAll(\PDO::FETCH_CLASS, $this->className, $this->constructorArgs);
}

private function insert($fields) {
$query = 'INSERT INTO `' . $this->table . '` (';
foreach ($fields as $key => $value) {
$query .= '`' . $key . '`,';
}
$query = rtrim($query, ',');
$query .= ') VALUES (';
foreach ($fields as $key => $value) {
$query .= ':' . $key . ',';
}
$query = rtrim($query, ',');
$query .= ')';
$fields = $this->processDates($fields);
$this->query($query, $fields);
}

private function update($fields) {
$query = ' UPDATE `' . $this->table .'` SET ';
foreach ($fields as $key => $value) {
$query .= '`' . $key . '` = :' . $key . ',';
}
$query = rtrim($query, ',');
$query .= ' WHERE `' . $this->primaryKey . '`
= :primaryKey';
// Set the :primaryKey variable
$fields['primaryKey'] = $fields['id'];
$fields = $this->processDates($fields);
$this->query($query, $fields);
}

public function delete($id ) {
$parameters = [':id' => $id];
$this->query('DELETE FROM `' . $this->table . '` WHERE
`' . $this->primaryKey . '` = :id', $parameters);
}


private function processDates($fields) {
foreach ($fields as $key => $value) {
if ($value instanceof \DateTime) {
$fields[$key] = $value->format('Y-m-d');
}
}
return $fields;
}

public function save($record) {
try {
if ($record[$this->primaryKey] == '') {
$record[$this->primaryKey] = null;
}
$this->insert($record);
}
catch (\PDOException $e) {
$this->update($record);
}
}




}