How to open and close connections with ADO.NET

ADO.NET enables applications to connect to data sources and manipulate the data.  In ADO.NET object model, the data is retrieved through a data provider. An application can access data either through a dataset or a data reader.

You have to create a connection and then provide connection string, to move data between data source and an application. SqlConnection class is used to open a connection and also have some more methods:

• ConnectionString: It is a property provides information like database name and data source.
• Open (): used to open a connection. It Needs connection string to open a connection.
• Close (): used to close an existing connection.

For example, the following code will create an object of SqlConnection class and then create a connection a connection string to the database in c# language.

SqlConnection connection = new SqlConnection();
connection.ConnectionString = “Data Source=(LocalDB)\v11.0;Initial Catalog=StockDb; Integrated Security=True”;

Here in the above code i have used the connection string of database name "StockDb". After you have defined the connection string, you need to open the connection by using open() method as written below
connection.Open();

Do all your work related to database and at the last you have to close the connection using close() method as written below
connection.Close();