How to establish a connection with Sql server using c#

[jeffreylee]

I am trying to establish a connection with sql server but i am not able to do so. Can some one help me out?

[jugosoft]

public void connect() 
{
    SqlConnection connection = new SqlConnection("connectionString");

    try {
         connection.Open();
    }
    catch {
         // Show error
    }
    finally {
         connection.Close();
    }
}

Don't forget to add

System.Data.SqlClient

reference to project.

[Mitja Bonca]

You can create a new connection from Server Explorer and copy connection strings from properties in your project. Following link contains steps to create connection from Server Explorer

http://msdn.microsoft.com/en-us/library/s4yys16a(v=VS.90).aspx

You can try following Connectionstring

Data Source=myServerAddress;Initial Catalog=myDataBase;User Id=myUsername;Password=myPassword;

You can also get list of connection string from http://connectionstrings.com/sql-server-2008

----------------------------------------------------------------------------------------------------

Do you know what is Connection string to database?

I have gave you all the information required in post above. You canot simply set the path to the database, and use it as a connection string. Connection string is consisted of more then one parameters. This is an example:

connectionString="Data Source=.\SQLEXPRESS;AttachDbFilename=C:\MyProject\dbRoomBooking.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True"

If you are in C#, you can create an applicaion configuration file (app.Config), which will be having the connection string, with its name:

(Example of app.Config):

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <configSections>
  </configSections>
  <connectionStrings>
    <add name="myConnString"
        connectionString="Data Source=.\SQLEXPRESS;AttachDbFilename=D:\AppsTest\Nov17RoomBooking\dbRoomBooking.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True"
        providerName="System.Data.SqlClient" />
  </connectionStrings>
</configuration>

So the code shoudl look like:

private static string sqlConnectionString = ConfigurationManager.ConnectionStrings["myConnString"].ConnectionString;
        
        private void DeletingDataBase()
        {
            using (SqlConnection sqlConn = new SqlConnection(sqlConnectionString))
            {
                using (SqlCommand cmd = new SqlCommand())
                {
                    string sqlQuery = "SELECT, INSERT, UPDATE, DELETE";
                    cmd.Connection = sqlConn;
                    cmd.CommandText = sqlQuery;
                    try
                    {
                        cmd.Connection.Open();
                        cmd.ExecuteNonQuery();
                    }
                    catch { }
                    finally
                    {
                        cmd.Connection.Close();
                    }
                }
            }
        }

ATTENTION: To use ConfigurationManager class, you have to add new Reference (right click on References in Solution explorer, and Add, go down to select System.Configuraton - and dont forget to add a new nameSpace on the top of the class, where you have the upper code I gave you:
using System.Configuration;

This tutorial explains all what you have to know to get your code working.

Mijta

[watsonsimler]

try this code..

        connetionString = "Data Source=ServerName;Initial Catalog=DatabaseName;User ID=UserName;Password=Password" 
        cnn = new SqlConnection(connetionString);
        try
        {
            cnn.Open();
            MessageBox.Show ("Connection Open ! ");
            cnn.Close();
        }
        catch (Exception ex)
        {
            MessageBox.Show("Can not open connection ! ");
        }

Source...SQL Server Connection

Watson

[vdixit01]

Connection = ConfigurationManager.ConnectionStrings["ContentTestConnection"].ToString();

Here ContentTestConnection is the name of the connection string whose values is the information about the the database connectivity.

using (MySqlConnection objconnection = new MySqlConnection(Connection))
                   using (MySqlCommand cmd = new MySqlCommand(query, objectconnection))
                {
                   objectconnection.Open();
                   cmd.ExecuteNonQuery();
                   objectconnection.Close();
                   }

I hope this helps.

Feel free to ask questions

[vdixit01]

Opening braces was missed . Corrected it

Vivek