Explain SqlConnection Object?

Answer

The first thing you will need to do when interacting with a data base is to create a connection. The connection tells the rest of the ADO.NET code which database it is talking to. It manages all of the low level logic associated with the specific database protocols. This makes it easy for you because the most work you will have to do in code is instantiate the connection object, open the connection, and then close the connection when you are done. Because of the way that other classes in ADO.NET are built, sometimes you don\'t even have to do that much work.

Although working with connections is very easy in ADO.NET, you need to understand connections in order to make the right decisions when coding your data access routines. Understand that a connection is a valuable resource. Sure, if you have a stand-alone client application that works on a single database one one machine, you probably don\'t care about this. However, think about an enterprise application where hundreds of users throughout a company are accessing the same database. Each connection represents overhead and there can only be a finite amount of them. To look at a more extreme case, consider a Web site that is being hit with hundreds of thousands of hits a day Applications that grab connections and don\'t let them go can have seriously negative impacts on performance and scalability.

Creating a SqlConnection Object

A SqlConnection is an object, just like any other C# object.  Most of the time, you just declare and instantiate the SqlConnection all at the same time, as shown below:

    SqlConnection conn = new SqlConnection(
        \"Data Source=(local);Initial Catalog=Northwind;Integrated Security=SSPI\");