How to update the database with new information-CodePudding

Good morning, I'm trying to make an ATM, I'm having a problem, I do not know how to save in the database the new information I'm entering.

decimal deposit = 0;
Console.WriteLine("\n Quanto deseja depositar ?"); //Ask how much the client want deposit
deposit = decimal.Parse(Console.ReadLine());
decimal value = depositarOperacao(debitCard, pin); /*goes to the database for the amount that the customer has in the account*/
decimal saldoAtual = value   deposit; /*calculation of the sum of the balance plus the deposit to give the current balance*/
Console.WriteLine("\n O seu saldo atual é de "   saldoAtual   " euro(s) \n Depósito: "   deposit   " euro(s)");
saldoAtual = updateSaldo(debitCard, pin, saldoAtual);

private static decimal updateSaldo(string numeroCartao, string pin, decimal saldoAtual)
{
    return getDbSaldo($@"UPDATE atmbd.atm Balance='{saldoAtual}' WHERE Pin='{pin}' AND CardNumber = '{numeroCartao}'");
}

private static decimal getDbUpdate(string query)
{
    using (var cn = new SqlConnection("Data Source=MAD-PC-023;Database=atmbd;Trusted_Connection=True;"))
    {
        cn.Open();
        using (var cmd = new SqlCommand() { Connection = cn, CommandText = query })
        {
            var reader = cmd.ExecuteReader();
            if (reader.Read() == true)
            {
                return reader.GetDecimal(0);
            }
            else
            {
                return 0;
            }
        }
    }
}

Now I have to put something save the current balance in the database in case the customer deposits more money add to the current balance.

CodePudding user response：

CommandText=$@"UPDATE atmbd.atm Balance=(Balance {deposit}) WHERE Pin='{pin}' AND CardNumber = '{numeroCartao}'");


var isUpdated=cmd.ExecuteNonQuery();

ExecuteNonQuery used to update,insert and delete.

ExecuteReader used to retrieve more than. ExecuteScalar return one field.

CodePudding user response：

For an update to the database table use the following.

private static bool Update(string cardNumber, string pin, decimal deposit)
{
    using (var cn = new SqlConnection("Data Source=MAD-PC-023;Database=atmbd;Trusted_Connection=True;"))
    {
        using var cmd = new SqlCommand
        {
            Connection = cn,
            CommandText = "UPDATE atmbd.atm SET Balance = Balance   @Deposit WHERE CardNumber = @CardNumber AND Pin = @Pin"
        };
        
        cmd.Parameters.Add("@CardNumber", SqlDbType.NChar).Value = cardNumber;
        cmd.Parameters.Add("@Pin", SqlDbType.NChar).Value = pin;
        cmd.Parameters.Add("@Deposit", SqlDbType.Decimal).Value = deposit;

        cn.Open();
        return cmd.ExecuteNonQuery() == 1;
    }
}