System.Data Namespace
Represents an open connection to a data source, and is implemented by .NET data providers that access relational databases.
| Class |
Description |
| OleDbConnection |
Represents an open connection to a data source. |
| SqlConnection |
Represents an open connection to an SQL Server™ database. This class cannot be inherited. |
The IDbConnection interface allows an inheriting class to implement a Connection class, which represents a unique session with a data source ( for example, a network connection to a server ). For more information about Connection classes, see ADO.NET Connections. For more information about implementing .NET data providers, see Implementing a .NET Data Provider.
An application does not create an instance of the IDbConnection interface directly, but initializes an instance of a class that inherits IDbConnection.
Classes that inherit IDbConnection must implement the inherited members, and typically define additional members to add provider-specific functionality. For example, the IDbConnection interface defines the ConnectionTimeout property. In turn, the IDbConnection class inherits this property, and also defines the PacketSize property.
Notes to Implementers: To promote consistency among .NET data providers, name the inheriting class in the form Prv Connection where Prv is the uniform prefix given to all classes in a specific .NET data provider namespace. For example, Sql is the prefix of the IDbConnection class in the System.Data.SqlClient namespace.
When you inherit from the IDbConnection interface, you should implement the following constructors:
| Item |
Description |
| PrvConnection ( ) |
Initializes a new instance of the PrvConnection class. |
| PrvConnection ( string connectionString ) |
Initializes a new instance of the PrvConnection class when given a string containing the connection string. |
The following examples illustrate using instances of SqlConnection and OleDbConnection — classes that derive from IDbConnection — to connect to a data source and display some of its properties.
Connecting to a Database
