Inserção

**********************************************************************Arquivo database.php

<?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;
    }
}
?>

****************************************************************************************Arquivo Empresa.php
<?php

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;
    }

    public function meuPrint(){

    echo "Meu Print"
    }
    // create product
    public function create()
    {
        //write query
        $query = "INSERT INTO " . $this->table_name . " (`razao_social`,`cnpj`,`inscricao_estadual`) VALUES (?,?,?)";

        $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;
        }

    }
}


?>

*********************************************************************************************************** cadastroEmpresa.php

<?php

        require_once ('php/database.php');
        require_once ('php/Empresa.php');



       if (isset($_POST['formularioCadastro'])) {
             $database = new Database();
             $empresa = new Empresa($database->getConnection());

             $empresa-> razao_social = $_POST['razaosocial'];
             $empresa-> cnpj = $_POST['cnpj'];
                 $empresa-> inscricao_estadual = $_POST['inscricaoestadual'];


            $empresa->meuPrint();
            $empresa->create();

             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>";
            }
            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>";
            }
        }

?>

<form method='post' name="formularioCadastro" class="form-horizontal localformcademp" >
  <div class="control-group ">

    <h3><label class="control-label " for="razaoSocial">Dados da Empresa</label></h3>
    <label class="control-label " for="razaoSocial">Razão Social</label>
    <div class="controls ">
      <input type="text" id="razaosocial" name="razaosocial" class="tamanhocampo" placeholder="">
    </div>
  </div>
  <div class="control-group">
    <label class="control-label" for="Cnpj">Cnpj</label>
    <div class="controls">
      <input type="text" id="cnpj" name="cnpj" class="tamanhocampo" placeholder="">
    </div>
    <div class="control-group">
    <label class="control-label" for="InscricaoEstadual">Inscrição Estadual</label>
    <div class="controls">
      <input type="text" id="inscricaoestadual" name="inscricaoestadual" class="tamanhocampo" placeholder="">
    </div>

 </br>
  </br>
      <button type="submit" class="btn">Salvar</button>

  </div>
</form>