The correct way to connect and query the SQL Server Express database

Question

I need a sample C # code (console application) that connects to the SQL Server Express database and inserts several variables into the Notebooks table

• SQL Server Express is @localhost
• username is the database
• and password - testdatabase

What is the right way to do this?

Answer 1

Core ADO.NET 101:

• establish a connection
• configure the command to execute
• execute this command

Step 1: setup the connection

You need to know the connection string to your database. See http://www.connectionstrings.com for tons of examples.

In your case, you say that this is a local instance of SQL Server Express, but, unfortunately, you did not specify what your database is called ..... your connection string will look something like this:

server=(local)\SQLEXPRESS;database=YourDatabaseName;user id=database;pwd=testdatabase 

Step 2: setting up the team

You can have different commands - selecting data, deleting it, or inserting data. Whatever you do, I would recommend always using parameterized queries to avoid SQL injection.

So your code looks something like this:

 string connectionString = "server=(local)\SQLEXPRESS;database=YourDatabaseName;user id=database;pwd=testdatabase"; string insertStmt = "INSERT INTO dbo.Laptops(Name, Model, ScreenSize) " + "VALUES(@Name, @Model, @Screensize)"; using(SqlConnection conn = new SqlConnection(connectionString)) using(SqlCommand cmd = new SqlCommand(insertStmt, conn)) { // set up the command parameters cmd.Parameters.Add("@Name", SqlDbType.VarChar, 100).Value = "ASUS SX30"; cmd.Parameters.Add("@Model", SqlDbType.VarChar, 50).Value = "Ultralight"; cmd.Parameters.Add("@Screensize", SqlDbType.Int).Value = 15; // open connection, execute command, close connection conn.Open(); int result = cmd.ExecuteNonQuery(); conn.Close(); }