Error doesn't let me update data into my database

Question

Error: Invalid column name 'Id'.'

I've been trying to make an update function, the logic behind it I think is fine, but it keeps throwing me this error mentioned above.

internal static void Uredi(Zahtjev odabraniZapis)
        {
            DB.OpenConnection();
            string sql = $"UPDATE Zahtjev_za_nabavu SET Ponuda = '{odabraniZapis.Ponuda}', Opis_predmeta = '{odabraniZapis.Opis_predmeta}', Cijena = '{odabraniZapis.Cijena}', ID_zaposlenika = {odabraniZapis.ID_zaposlenika} WHERE ID_zahtjeva = {odabraniZapis.ID_zahtjeva};";
            DB.ExecuteCommand(sql);
            DB.CloseConnection();
        }

This above is the function that I call to Update existing data.

I get the row that i want to change through ID_zahtjeva .

And this is the function that calls the UPDATE function.

private void btnAzuriraj_Click(object sender, EventArgs e)
        {
            Zahtjev noviZahtjev = new Zahtjev(int.Parse(txtZahtjev.Text), txtPonuda.Text, txtOpis.Text, txtCijena.Text, int.Parse(txtZaposlenik.Text));

            var provjera = ZahtjeviRepository.GetZahtjevi(noviZahtjev.ID_zahtjeva);
            if(provjera == null)
            {
                ZahtjeviRepository.Kreiraj(noviZahtjev);
                this.Close();
            }
            else
            {
                ZahtjeviRepository.Uredi(noviZahtjev);
                this.Close();
            }
        }