Update does not commit bank changes

Question

Good night, you guys! I’m new to ASP NET MVC and I’m making a CRUD simple with bench Postgresql. I’ve already implemented the Insert, delete and Get, but the Update is not saving the changes in the bank. Debugging, I realized that it does all the steps correctly, until the "commit" of UPDATE, but when I give GET again for that record, it remains the same. No error returns or nothing. Follow my method below:

 public Guid Update(AreaInteresse area)
    {
        using (NpgsqlConnection con = new NpgsqlConnection(connectionString))
        {
            con.Open();
            //Inicia a transação
            using (var trans = con.BeginTransaction())
            {
                try
                {
                    NpgsqlCommand cmd = new NpgsqlCommand();
                    cmd.Connection = con;
                    cmd.Transaction = trans;
                    cmd.CommandText = @"UPDATE areainteresse SET descricao=@descricao WHERE id= @id";
                    cmd.Parameters.AddWithValue("id", Convert.ToString(area.Id));
                    cmd.Parameters.AddWithValue("descricao", area.Descricao);
                    cmd.ExecuteNonQuery();

                    //commit na transação
                    trans.Commit();
                    return area.Id;

                }
                catch (Exception ex)
                {
                    //rollback da transação
                    trans.Rollback();
                    throw ex;
                }
                finally
                {
                    con.Close();
                }
            }
        }

Does anyone have any idea what it could be? It seems that he is not executing the "COMMIT" in the database, because the ID arrives correctly to the Parameter and converts it to string because the database field is a Character Varying (36).