Generic coding with the ADO.NET common base classes

The .NET Framework, versions 2.0, 3.0, and 3.5, features a namespace called System.Data.Common, which features a set of base classes that can be shared by any .NET data provider. This facilitates a generic ADO.NET database application development approach, featuring a constant programming interface across different databases.

  DbProviderFactory factory = DbProviderFactories.GetFactory("IBM.Data.DB2");
  DbConnection conn = factory.CreateConnection();
  DbConnectionStringBuilder sb = factory.CreateConnectionStringBuilder();

  if( sb.ContainsKey( "Database" ) )
  {
     sb.Remove( "database" );
     sb.Add( "database", "SAMPLE" );
  }

  conn.ConnectionString = sb.ConnectionString;

  conn.Open();

The DbProviderFactory object is the point where any generic ADO.NET application begins. This object creates generic instances of .NET data provider objects, such as connections, data adapters, commands, and data readers, which work with a specific database product. In the previous example, the "IBM.Data.DB2" string passed into the GetFactory method uniquely identifies the IBM® Data Server Provider for .NET, and results in the initialization of a DbProviderFactory instance that creates database provider object instances specific to the IBM Data Server Provider for .NET.

The DbConnection object can connect to DB2® family Informix® databases, just as a DB2Connection object, which is actually inherited from DbConnection. Using the DbConnectionStringBuilder class, you can determine the connection string keywords for a data provider, and generate a custom connection string. The code in the previous example checks if a keyword named "database" exists in the IBM Data Server Provider for .NET, and if so, generates a connection string to connect to the SAMPLE database.