How can I set a SQL Server connection string in a C# application?

General Discussions
1

I’m developing a C# application and know the SQL Server connection string (server name, password, etc.) for my PC. However, on another PC, the connection string is different. Is there a default SQL Server account that can be used across machines?

I’ve heard about the SA account. What is it, and how does it relate to SQL Server connection string setup?

2

Hey! I’ve dealt with this scenario a lot :sweat_smile:. In a C# application, you usually store your SQL Server connection string in the code like this:

string connectionString = @"Server=YOUR_SERVER_NAME;Database=YOUR_DB_NAME;User Id=YOUR_USERNAME;Password=YOUR_PASSWORD;";
using (SqlConnection connection = new SqlConnection(connectionString))
{
    connection.Open();
    // your DB code here
}

A few things I usually keep in mind:

Replace YOUR_SERVER_NAME with the machine name or IP.

Replace YOUR_USERNAME and YOUR_PASSWORD with your SQL login credentials.

Using using ensures the connection is properly closed.

This works perfectly on your machine, but as you noticed, the connection string changes on another PC.

3

I’ve been asked this a lot by beginners. The sa account is the system administrator account for SQL Server. Technically, you could use it, but I usually avoid it because:

  • It has full admin privileges (so mistakes can be catastrophic).

  • It’s often disabled or has a different password on other machines.

  • For security, it’s better to create a separate SQL login with only the permissions your app needs.

In practice, I create a SQL Server login like app_user and give it access to the database, then use that in the connection string.

4

Since connection strings vary across machines, I usually store them in a configuration file instead of hardcoding them:

App.config / Web.config example:

<connectionStrings>
    <add name="MyDb" 
         connectionString="Server=SERVER_NAME;Database=DB_NAME;User Id=USERNAME;Password=PASSWORD;" 
         providerName="System.Data.SqlClient" />
</connectionStrings>

Then in C#:

string connStr = ConfigurationManager.ConnectionStrings["MyDb"].ConnectionString;
using (SqlConnection conn = new SqlConnection(connStr))
{
    conn.Open();
}

I like this approach because you can change the connection string per machine without touching the code.

Super handy when deploying apps across multiple PCs or environments.