Question

why isn’t it possible to define another key than
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
private Key key;
?
If i try to define a @PrimaryKey as say, an Integer I get an Server Error…
http://code.google.com/intl/de-DE/appengine/docs/java/datastore/dataclasses.html

Answer 1

Yes, you can use a Long

@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
private Long id;

or a String

@PrimaryKey
private String name;

See http://code.google.com/appengine/docs/java/datastore/creatinggettinganddeletingdata.html