Php query builder

<?php

// Database configuration
$dbHost = 'localhost'; // Change this to your database host
$dbName = 'your_database_name'; // Change this to your database name
$dbUser = 'your_username'; // Change this to your database username
$dbPass = 'your_password'; // Change this to your database password

// PDO connection
try {
    $pdo = new PDO("mysql:host=$dbHost;dbname=$dbName", $dbUser, $dbPass);
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch (PDOException $e) {
    die("Error: " . $e->getMessage());
}
?>

<?php

require 'dbconfig.php';

class QueryBuilder {
    protected $pdo;
    protected $table;
    protected $where = [];
    protected $bindings = [];

    public function __construct(PDO $pdo) {
        $this->pdo = $pdo;
    }

    public function table($table) {
        $this->table = $table;
        return $this;
    }

    public function where($column, $operator, $value) {
        $this->where[] = "$column $operator ?";
        $this->bindings[] = $value;
        return $this;
    }

    public function select($columns = '*') {
        $sql = "SELECT $columns FROM $this->table";
        if (!empty($this->where)) {
            $sql .= " WHERE " . implode(' AND ', $this->where);
        }
        $statement = $this->pdo->prepare($sql);
        $statement->execute($this->bindings);
        return $statement->fetchAll(PDO::FETCH_ASSOC);
    }

    public function insert($data) {
        $columns = implode(', ', array_keys($data));
        $values = implode(', ', array_fill(0, count($data), '?'));
        $sql = "INSERT INTO $this->table ($columns) VALUES ($values)";
        $statement = $this->pdo->prepare($sql);
        $statement->execute(array_values($data));
        return $this->pdo->lastInsertId();
    }

    public function update($data) {
        $set = [];
        foreach ($data as $key => $value) {
            $set[] = "$key = ?";
            $this->bindings[] = $value;
        }
        $set = implode(', ', $set);
        $sql = "UPDATE $this->table SET $set WHERE " . implode(' AND ', $this->where);
        $statement = $this->pdo->prepare($sql);
        $statement->execute($this->bindings);
        return $statement->rowCount();
    }

    public function delete() {
        $sql = "DELETE FROM $this->table WHERE " . implode(' AND ', $this->where);
        $statement = $this->pdo->prepare($sql);
        $statement->execute($this->bindings);
        return $statement->rowCount();
    }

    public function rawQuery($sql, $bindings = []) {
        $statement = $this->pdo->prepare($sql);
        $statement->execute($bindings);
        return $statement->fetchAll(PDO::FETCH_ASSOC);
    }
}

// Usage example:
$queryBuilder = new QueryBuilder($pdo);

// Method chaining example
$users = $queryBuilder->table('users')->where('age', '>', 18)->select();
print_r($users);

// Insert example
$newUserId = $queryBuilder->table('users')->insert(['name' => 'Jane Doe', 'age' => 25, 'email' => 'jane@example.com']);
echo "New user ID: $newUserId";

// Update example
$updatedRows = $queryBuilder->table('users')->where('id', '=', 1)->update(['age' => 30, 'name' => 'Updated Name']);
echo "Updated rows: $updatedRows";

// Delete example
$deletedRows = $queryBuilder->table('users')->where('id', '=', 2)->delete();
echo "Deleted rows: $deletedRows";

// Raw query example
$customQuery = "SELECT * FROM users WHERE age > ?";
$results = $queryBuilder->rawQuery($customQuery, [20]);
print_r($results);