Base Classes and Provider Factory Classes

3.1 Base Classes and Provider Factory Classes

With ADO.NET, data classes derive from the base classes defined in the System.Data.Common namespace. Developers can create provider-specific instances of these base classes using provider factory classes.

Provider factory classes allow generic data access code to access multiple data sources with a minimum of data source-specific code. This reduces much of the conditional logic currently used by applications accessing multiple data sources.

Using Oracle Data Provider for .NET, the OracleClientFactory class can be returned and instantiated, enabling an application to create instances of the following ODP.NET classes that inherit from the base classes:

Table 3-1 ODP.NET Classes that Inherit from ADO.NET 2.0 Base Classes

ODP.NET Classes	Inherited from ADO.NET 2.0 Base Class
`OracleClientFactory`	`DbProviderFactory`
`OracleCommand`	`DbCommand`
`OracleCommandBuilder`	`DbCommandBuilder`
`OracleConnection`	`DbConnection`
`OracleConnectionStringBuilder`	`DbConnectionStringBuilder`
`OracleDataAdapter`	`DbDataAdapter`
`OracleDataReader`	`DbDataReader`
`OracleDataSourceEnumerator`	`DbDataSourceEnumerator`
`OracleException`	`DbException`
`OracleParameter`	`DbParameter`
`OracleParameterCollection`	`DbParameterCollection`
`OracleTransaction`	`DbTransaction`

In general, applications still require Oracle-specific connection strings, SQL or stored procedure calls, and declare that a factory from ODP.NET is used.