Hello Anna,
Have you tried something along these lines: have a link persistent
entity class (as a link "table"). Each instance of this class stores
the encoded (primary) key string of a related pair of Entity1 and
Entity2 instances? (This approach does not describe the entity parent-
child structure of all these entities.)
Example persistent entity class code follows.
Cheers,
Ian
@PersistenceCapable(identityType = IdentityType.APPLICATION,
detachable = "true")
public class ManyToManyLink implements Serializable
{
private static final long serialVersionUID = 1L;
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
@Extension(vendorName="datanucleus", key="gae.encoded-pk",
value="true")
private String sEncodedKey;
@Persistent
private String sEKEntity1;
@Persistent
private String sEKEntity2;
}
@PersistenceCapable(identityType = IdentityType.APPLICATION,
detachable = "true")
public class Entity1 implements Serializable
{
private static final long serialVersionUID = 1L;
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
@Extension(vendorName="datanucleus", key="gae.encoded-pk",
value="true")
private String sEncodedKey;
}
@PersistenceCapable(identityType = IdentityType.APPLICATION,
detachable = "true")
public class Entity2 implements Serializable
{
private static final long serialVersionUID = 1L;
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
@Extension(vendorName="datanucleus", key="gae.encoded-pk",
value="true")
private String sEncodedKey;
}
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