SQL Connection Object

To create an SQL Connection object, we have to use the SqlConnection class. For this, the following steps are taken:

(a) Create a connection string: The connection string provides the necessary information to connect to the database. An example of this is:

string connectionString = "Data Source=SERVER_NAME;Initial Catalog=DATABASE_NAME;User ID=USER_NAME;Password=PASSWORD;";

using System.Data.SqlClient;

SqlConnection sqlConnection = new SqlConnection(connectionString);

To read or update data using an SQL Connection, follow these steps:

(a) Open the SQL connection: sqlConnection.Open();

(b) Use an SQL Command: The SqlCommand object is used to execute an SQL query on the database.

SqlCommand sqlCommand = new SqlCommand("SELECT * FROM Employees", sqlConnection);

(c) Get the data: SqlDataReader is used to read the data.

SqlDataReader reader = sqlCommand.ExecuteReader();

while (reader.Read())

{

    Console.WriteLine(reader["EmployeeName"]);

}

sqlConnection.Close();

Complete code of the SQL Connection Object:

using System;

using System.Data.SqlClient;

class Program

{

    static void Main()

    {

        string connectionString = "Data Source=SERVER_NAME;Initial Catalog=DATABASE_NAME;User ID=USER_NAME;Password=PASSWORD;";

        // Creating an SQL Connection Object

        using (SqlConnection sqlConnection = new SqlConnection(connectionString))

        {

            try

            {

                // Opening the connection

                sqlConnection.Open();

                Console.WriteLine("Connection Opened Successfully!");

                // Creating and executing an SQL Command

                SqlCommand sqlCommand = new SqlCommand("SELECT * FROM Employees", sqlConnection);

                SqlDataReader reader = sqlCommand.ExecuteReader();

                // Reading the data

                while (reader.Read())

                {

                    Console.WriteLine("Employee Name: " + reader["EmployeeName"]);

                }

                reader.Close();

            }

            catch (Exception ex)

            {

                Console.WriteLine("Error: " + ex.Message);

            }

            finally

            {

                // Closing the connection

                sqlConnection.Close();

                Console.WriteLine("Connection Closed.");

            }

        }

    }

}