Connection Object in ADO.NET

The Connection Object

The Connection object is the first component of ADO.NET that you should be looking at. A connection sets a link between a data source and ADO.NET. A Connection object sits between a data source and a DataAdapter (via Command). You need to define a data provider and a data source when you create a connection. With these two, you can also specify the user ID and password depending on the type of data source. Figure 3-3 shows the relationship between a connection, a data source, and a data adapter.


Figure 1: The relationship between connection, data Adapter, and a data source

Connection can also be connected to a Command object to execute SQL queries, which can be used to retrieve, add, update and delete data to a data source. Figure 2 shows the relationship between the Command and Connection objects.


Figure 2: The relationship between the command object and connection object

The Connection object also plays a useful role in creating a transaction. Transactions are stored in transactions objects, and transaction classes have all those nice features for dealing with transactions such as commit and rollback. Figurer 3 shows the relationship between the connection object and transaction.


Figure 3: Creating a transaction from a connection object

Each data provider has a Connection class. Below Table shows the name of various connection classes for data providers.

Table: Data provider connection classes

OleDb OleDbConnection
Sql SqlConnection
ODBC OdbcConnection


Hope this article would have helped you in understanding ADO.NET Connection object. See my other articles on the website on ADO.NET.