C# MySQL Windows form application
To preface this question I am learning development in C# on my own, no classes or formal training.
I am writing a very simple app to get familiarized with windows forms and databases. I have a working app, however; if I want to add a new field in the database, then go to the class where I list all my fields with public string or int. Then go to the DAO I created, where have it reading the table. I always get NULL issue, if I back out the new field in all the locations everything works again.
Sample of the class
namespace csapp
public class Customers
{
public int CustomerID { get; set; }
public string? BusinessName { get; set; }
public string? LastName { get; set; }
public string? FirstName { get; set; }....
addition when it breaks
public string? OtherPhone {get;set;}
Sample of the DAO file
internal class csappDAO
{
string connectionString = "datasource=localhost;port=3306;username=admin;password=admin;database=csappdb;";
public List<Customers> getAllCustomers()
{
// start with an empty list
List<Customers> returnThese = new List<Customers>();
// connect to the mysql server
MySqlConnection connection = new MySqlConnection(connectionString);
connection.Open();
// define the sql statement to fetch all customers
MySqlCommand command = new MySqlCommand("SELECT * FROM customers", connection);
using (MySqlDataReader reader = command.ExecuteReader())
{
while (reader.Read())
{
Customers a = new Customers
{
CustomerID = reader.GetInt32(0),
BusinessName = reader.GetString(1),
LastName = reader.GetString(2),
FirstName = reader.GetString(3),...
addition when it breaks
OtherPhone=reader.GetString(21)
Hopefully this makes since
I am writing a very simple app to get familiarized with windows forms and databases. I have a working app, however; if I want to add a new field in the database, then go to the class where I list all my fields with public string or int. Then go to the DAO I created, where have it reading the table. I always get NULL issue, if I back out the new field in all the locations everything works again.
Sample of the class
namespace csapp
public class Customers
{
public int CustomerID { get; set; }
public string? BusinessName { get; set; }
public string? LastName { get; set; }
public string? FirstName { get; set; }....
addition when it breaks
public string? OtherPhone {get;set;}
Sample of the DAO file
internal class csappDAO
{
string connectionString = "datasource=localhost;port=3306;username=admin;password=admin;database=csappdb;";
public List<Customers> getAllCustomers()
{
// start with an empty list
List<Customers> returnThese = new List<Customers>();
// connect to the mysql server
MySqlConnection connection = new MySqlConnection(connectionString);
connection.Open();
// define the sql statement to fetch all customers
MySqlCommand command = new MySqlCommand("SELECT * FROM customers", connection);
using (MySqlDataReader reader = command.ExecuteReader())
{
while (reader.Read())
{
Customers a = new Customers
{
CustomerID = reader.GetInt32(0),
BusinessName = reader.GetString(1),
LastName = reader.GetString(2),
FirstName = reader.GetString(3),...
addition when it breaks
OtherPhone=reader.GetString(21)
Hopefully this makes since
