数据访问
System.Data
l DataSet
l DataTable
l IDataAdapter
l IDataReader
l 强类型的数据集
Ø 在 VS 中不支持
Ø 可以手工修改自动产生的代码

| The System.DAta and System.Data.Common namespaces expose the same types that you are familiar with from ADO.NET on the desktop. The DataSet and DataTable classes available here offer nearly identical functionality as their desktop counterparts. The IDataAdapter and IDataReader describe the same interfaces and are used by both the Sql Server and Sql Server CE APIs.
| Unfortunately, Visual Studio does not currently support Typed DataSets. If you explore, you will find that you can still create an XML Schema and generate a DataSet from that schema in a device project. However, the generated code will not compile against the Compact Framework, because it references numerous classes that are not available.
| You can manually manipulate the generated code, however, by simply deleting the offending attributes and procedures (there are about six of them). The result will be a typed data set that will compile and run as expected. However, if you make any changes to your schema, Visual Studio will overwrite your changes. You can avoid this condition by copying your cleaned code into a separate file that is not associated with the schema.