Notes

// See https://aka.ms/new-console-template for more information

using System;
using System.Data;
using System.Data.SqlClient;

class Program
{
SqlConnection conn;
public Program()
{
conn = new SqlConnection(
"Data Source=REETU-SINGH-LP\PSSQL;Initial Catalog=prac1810;User id=sa;Password=ps@123");
}
static void Main()
{
Program sqlobject = new Program();
Console.WriteLine("connection successful");
Console.WriteLine("Tables before insert, update and delete commands....................");
sqlobject.ReadData();
Console.WriteLine("-------------------------------------------------------------");
sqlobject.InsertData();
Console.WriteLine();
Console.WriteLine("After insert....................");
sqlobject.ReadData();
Console.WriteLine("-------------------------------------------------------------");
sqlobject.UpdateData();
Console.WriteLine();
Console.WriteLine("After update....................");
sqlobject.ReadData();
Console.WriteLine("-------------------------------------------------------------");
sqlobject.DeleteData();
Console.WriteLine();
Console.WriteLine("After delete....................");
sqlobject.ReadData();
}
public void ReadData()
{
SqlDataReader reader = null;
try
{
conn.Open();
SqlCommand cmd = new SqlCommand("select * from countries", conn);
reader = cmd.ExecuteReader();
while (reader.Read())
{
Console.WriteLine(reader[0] + " " + reader[1] + " " + reader[2]);
Console.WriteLine();
}
}
finally
{
if (reader != null)
{
reader.Close();
}
if (conn != null)
{
conn.Close();
}
}
}

public void InsertData()
{
try
{
conn.Open();
string insertstr = @"
insert into countries
(code,[name],continent_name)
values (101,'Virginia','Mystic falls')";
SqlCommand cmd = new SqlCommand(insertstr, conn);
cmd.ExecuteNonQuery();
}
finally
{
if (conn != null)
{
conn.Close();
}
}
}

public void UpdateData()
{
try
{
conn.Open();
string updatestr = @"
update merchants
set merchant_name='Cole'
where merchant_name='Ethan'";
SqlCommand cmd = new SqlCommand(updatestr);
cmd.Connection = conn;
cmd.ExecuteNonQuery();
}
finally
{
if (conn != null)
{
conn.Close();
}
}
}

public void DeleteData()
{
try
{
conn.Open();
string delstr = @"
delete from countries
where code=101";
SqlCommand cmd = new SqlCommand();
cmd.CommandText = delstr;
cmd.Connection = conn;
cmd.ExecuteNonQuery();
}
finally
{
if (conn != null)
{
conn.Close();
}
}
}

}