C# - How can I do MS SQL Server Connection?

Question

I started programming recently and at the moment I am developing a program with SQL Server 2019 and Visual Studio 2019 in C# that performs simple functions for inserting, deleting and displaying data but I cannot understand how to set up the initial connection with SQL Server. I already connected the Database from Tools->Connect to Database... and the connection test was successful, but now I don't know how to set the connection via SQL Server Authentication by code.

Answer 1

It all depends how you want create the connection really..

At the very top of your form be sure to include

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

---

Depending on how you want to create the connection on whatever button trigger or page load... this scenario would be for you to get specific fields of a query:

string qString = "SELECT value1,value2,value3 FROM database WHERE value 1 = 'hello world'";

using(SqlConnection connection0 = new SqlConnection(ConfigurationManager.ConnectionStrings["CONNECTION_STRING_NAME_HERE"].ToString()))
using(SqlCommand command0 = connection0.CreateCommand())
{
    command0.CommandText = qString;

    connection0.Open();

    using (SqlDataReader reader = command0.ExecuteReader())
    {
        while (reader.Read())
        {
            value1string = reader["value1"].ToString();
            value2string = reader["value2"].ToString();
            value3string = reader["value3"].ToString();
        }
    }

    connection0.Close();
}

Be sure to add the connection string to the app.config file:

<connectionStrings>
    <add name="CONNECTION_STRING_NAME_HERE" 
         connectionString="Data Source=SERVERINSTANCENAME;Initial Catalog=YOUR_DATABASE_NAME;User ID=DATABASE_USERNAME;Password=DATABASE_USER_PASSWORD;" />
</connectionStrings>