Crud

<?
if($_POST){

    // instantiate Empresa object
    include_once 'php/Empresa.php';
    $empresa = new Empresa($db);

    // set Empresa property values
    $empresa->razao_social = $_POST['razaosocial'];
    $empresa->cnpj = $_POST['cnpj'];
    $empresa->inscricao_estadual = $_POST['inscricaoestadual'];

    // create the Empresa
    if($empresa->create()){
        echo "<div class=\"alert alert-success alert-dismissable\">";
            echo "<button type=\"button\" class=\"close\" data-dismiss=\"alert\" aria-hidden=\"true\">&times;</button>";
            echo "Empresa Cadastrada.";
        echo "</div>";
    }

    // if unable to create the Empresa, tell the user
    else{
        echo "<div class=\"alert alert-danger alert-dismissable\">";
            echo "<button type=\"button\" class=\"close\" data-dismiss=\"alert\" aria-hidden=\"true\">&times;</button>";
            echo "Erro ao Cadastrar.";
        echo "</div>";
    }
}
?>

// Class Empresa

<?

     public class Empresa{

    //base de dados e nome da tabela

    private $conn;
    private $table_name = "cadastro_emp";

    //propriendades da Classe

    $public razao_social;
    $public cnpj;
    $public inscricao_estadual;


     public function __construct($db){
        $this->conn = $db;
    }

    // create product
    function create(){

        // to get time-stamp for 'created' field
        $this->getTimestamp();

        //write query
        $query = "INSERT INTO
                    " . $this->table_name . "
                SET
                    razao_social = ?, cnpj = ?, inscricao_estadual = ?";

        $stmt = $this->conn->prepare($query);

        $stmt->bindParam(1, $this->razao_social);
        $stmt->bindParam(2, $this->cnpj);
        $stmt->bindParam(3, $this->inscricao_estadual);

        if($stmt->execute()){
            return true;
        }else{
            return false;
        }

    }
}

//Class Conexão


<?php
class Database{

    // specify your own database credentials
    private $host = "127.0.0.1";
    private $db_name = "sisim";
    private $username = "root";
    private $password = "";
    public $conn;

    // get the database connection
    public function getConnection(){

        $this->conn = null;

        try{
            $this->conn = new PDO("mysql:host=" . $this->host . ";dbname=" . $this->db_name, $this->username, $this->password);
        }catch(PDOException $exception){
            echo "Connection error: " . $exception->getMessage();
        }

        return $this->conn;
    }
}
?>