SqlCommand Class ADO.Net | ExecuteNonQuery | ExecuteReader

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using System.Data;

using System.Data.SqlClient;

using System.Configuration;

namespace SQLConnectionADO

{

internal class Program

{

static void Main(string[] args)

{

Program.Connection();

Console.ReadLine();

}

static void Connection()

{

string cs = ConfigurationManager.ConnectionStrings["dbcs"].ConnectionString;

SqlConnection con = null;

try

{

using (con = new SqlConnection(cs))

{

//NOTE:Scalar functions can take multiple values and always returns single value

//string query = "select max(salary) from employee_tbl";

//string query = "select min(salary) from employee_tbl";

//string query = "select count(salary) from employee_tbl";

string query = "select sum(salary) from employee_tbl";

SqlCommand cmd = new SqlCommand(query, con);

con.Open();

int a = (int)cmd.ExecuteScalar();

Console.WriteLine(a);

}

catch (Exception ex)

{

Console.WriteLine(ex.Message);

}

finally

{

con.Close();

}

//static void Connection()

//{

// string cs = ConfigurationManager.ConnectionStrings["dbcs"].ConnectionString;

// SqlConnection con = null;

// try

// {

// using (con = new SqlConnection(cs))

// {

// Console.WriteLine("Employee ID : ");

// string id = Console.ReadLine();

// string query = "delete from employee_tbl where id=@id";

// SqlCommand cmd = new SqlCommand(query, con);

// cmd.Parameters.AddWithValue("@id", id);

// con.Open();

// int a = cmd.ExecuteNonQuery();

// if (a > 0)

// {

// Console.WriteLine("Data has been Deleted Successfully....");

// }

// else

// {

// Console.WriteLine("Data Deletion Failed....");

// }

// catch (Exception ex)

// {

// Console.WriteLine(ex.Message);

// }

// finally

// {

// con.Close();

// }

//}

//static void Connection()

//{

// string cs = ConfigurationManager.ConnectionStrings["dbcs"].ConnectionString;

// SqlConnection con = null;

// try

// {

// using (con = new SqlConnection(cs))

// {

// Console.WriteLine("Employee ID : ");

// string id = Console.ReadLine();

// Console.WriteLine("Employee Name : ");

// string name = Console.ReadLine();

// Console.WriteLine("Employee Gender : ");

// string gender = Console.ReadLine();

// Console.WriteLine("Employee Age : ");

// string age = Console.ReadLine();

// Console.WriteLine("Employee Salary : ");

// string salary = Console.ReadLine();

// Console.WriteLine("Employee City : ");

// string city = Console.ReadLine();

// string query = "update employee_tbl set name=@name,gender=@gender,age=@age,salary=@salary,city=@city where id=@id";

// SqlCommand cmd = new SqlCommand(query, con);

// cmd.Parameters.AddWithValue("@id", id);

// cmd.Parameters.AddWithValue("@name", name);

// cmd.Parameters.AddWithValue("@gender", gender);

// cmd.Parameters.AddWithValue("@age", age);

// cmd.Parameters.AddWithValue("@salary", salary);

// cmd.Parameters.AddWithValue("@city", city);

// con.Open();

// int a = cmd.ExecuteNonQuery();

// if (a > 0)

// {

// Console.WriteLine("Data has been Updated Successfully....");

// }

// else

// {

// Console.WriteLine("Data Updation Failed....");

// }

// catch (Exception ex)

// {

// Console.WriteLine(ex.Message);

// }

// finally

// {

// con.Close();

// }

//}

//static void Connection()

//{

// string cs = ConfigurationManager.ConnectionStrings["dbcs"].ConnectionString;

// SqlConnection con = null;

// try

// {

// using (con = new SqlConnection(cs))

// {

// Console.WriteLine("Employee Name : ");

// string name = Console.ReadLine();

// Console.WriteLine("Employee Gender : ");

// string gender = Console.ReadLine();

// Console.WriteLine("Employee Age : ");

// string age = Console.ReadLine();

// Console.WriteLine("Employee Salary : ");

// string salary = Console.ReadLine();

// Console.WriteLine("Employee City : ");

// string city = Console.ReadLine();

// string query = "insert into employee_tbl values(@name,@gender,@age,@salary,@city)";

// SqlCommand cmd = new SqlCommand(query, con);

// cmd.Parameters.AddWithValue("@name", name);

// cmd.Parameters.AddWithValue("@gender", gender);

// cmd.Parameters.AddWithValue("@age", age);

// cmd.Parameters.AddWithValue("@salary", salary);

// cmd.Parameters.AddWithValue("@city", city);

// con.Open();

// int a = cmd.ExecuteNonQuery();

// if (a > 0)

// {

// Console.WriteLine("Data has been insertd Successfully....");

// }

// else

// {

// Console.WriteLine("Data Insertion Failed....");

// }

// catch (Exception ex)

// {

// Console.WriteLine(ex.Message);

// }

// finally

// {

// con.Close();

// }

//}

//static void Connection()

//{

// string cs = ConfigurationManager.ConnectionStrings["dbcs"].ConnectionString;

// SqlConnection con = null;

// try

// {

// using (con = new SqlConnection(cs))

// {

// //1st way

// //string query = "spGetEmployees";

// //SqlCommand cmd = new SqlCommand(query,con);

// //cmd.CommandType = CommandType.StoredProcedure;

// //2nd way

// //string query = "select * from employee_tbl";

// ////SqlCommand cmd = new SqlCommand(query,con);

// //SqlCommand cmd = new SqlCommand();

// //cmd.CommandText = query;

// //cmd.Connection = con;

// //con.Open();

// //SqlDataReader dr = cmd.ExecuteReader();

// //while(dr.Read())

// //{

// // Console.WriteLine("Id = " + dr["id"] + ", Name = " + dr["name"] + ", Gender = " + dr["gender"] + ", Age = " + dr["age"] + ", Salary = " + dr["salary"] + ", City = " + dr["city"]);

// //}

// }

// catch (Exception ex)

// {

// Console.WriteLine(ex.Message);

// }

// finally

// {

// con.Close();

// }

//}

//static void Connection()

//{

// string cs = ConfigurationManager.ConnectionStrings["dbcs"].ConnectionString;

// SqlConnection con = null;

// try

// {

// using (con = new SqlConnection(cs))

// {

// con.Open();

// if (con.State == ConnectionState.Open)

// {

// Console.WriteLine("Connection has been Created Successfully !!");

// }

// catch (SqlException ex)

// {

// Console.WriteLine(ex.Message);

// }

// finally

// {

// con.Close();

// }

//}

//static void Connection()

//{

// string cs = "Data Source=HEER\\SQLEXPRESS;Initial Catalog=ado_d;Integrated Security=true;";

// SqlConnection con = null;

// try

// {

// using (con = new SqlConnection(cs))

// {

// con.Open();

// if (con.State == ConnectionState.Open)

// {

// Console.WriteLine("Connection has been Created Successfully !!");

// }

// catch (SqlException ex)

// {

// Console.WriteLine(ex.Message);

// }

// finally

// {

// con.Close();

// }

// //using(SqlConnection con = new SqlConnection(cs))

// //{

// // con.Open();

// // if (con.State == ConnectionState.Open)

// // {

// // Console.WriteLine("Connection has been created successfully.");

// // }

// //}

// //SqlConnection con = new SqlConnection(cs);

// //try

// //{

// // con.Open();

// // if (con.State == ConnectionState.Open)

// // {

// // Console.WriteLine("Connection has been created successfully.");

// // }

// //}

// //catch (SqlException ex)

// //{

// // Console.WriteLine(ex.Message);

// //}

// //finally

// //{

// // con.Close();

// //}

//}

}

Above File is SQLConnectionADO\Program.cs

<?xml version="1.0" encoding="utf-8" ?>

</startup>

</connectionStrings>

</configuration>

Above File is SQLConnectionADO\App.config