[google-appengine] One-to-many relation problem
Hi All,
I'm trying to use the one-to-many relation with heritance but without
success. Let me explain.
I have 3 classes :
@PersistenceCapable
@Inheritance(strategy = InheritanceStrategy.SUBCLASS_TABLE)
public abstract class Op {
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
public Key key;
@Persistent(mappedBy = "op")
@Element(dependent = "true")
private ArrayList entryArr = new ArrayList();
}
@PersistenceCapable
public class ExtendedOp extends Op {
public double quota;
}
@PersistenceCapable
public class Entry {
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
public Key key;
@Persistent
private Op op = null;
}
When I persist, I use this code :
ExtendedOp op = new ExtendedOp();
op.addNewEntry(new Entry());
op.addNewEntry(new Entry());
pm.makePersistent(op);
After, I persisted, I reload the "ExtendedOp" with this :
String connectionQuery = "select from " + ExtendedOp.class.getName();
opArr = (List) pm.newQuery(connectionQuery).execute();
if (opArr != null) {
for (ExtendedOp opExt : opArr) {
if ( opExt.getEntryArr() != null)
for (Entry entry : sale.getEntryArr()) {
System.out.println("ok"); //works!
if (entry.getOp() != null)
System.out.println("perfect"); //never
display
}
}
}
The problem is : the Entry has the field "operation" always null. This
field is from the relation one-to-many. Maybe this field is still null
because is class type is "parent" of ExtendedOp?
Could you help me to solve that problem?
Thanks you very much,
Bat
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[google-appengine] One-to-many relation problem
Hi All,
I'm trying to use the one-to-many relation with heritance but without
success. Let me explain.
I have 3 classes :
@PersistenceCapable
@Inheritance(strategy = InheritanceStrategy.SUBCLASS_TABLE)
public abstract class Op {
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
public Key key;
@Persistent(mappedBy = "op")
@Element(dependent = "true")
private ArrayList entryArr = new ArrayList();
}
@PersistenceCapable
public class ExtendedOp extends Op {
public double quota;
}
@PersistenceCapable
public class Entry {
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
public Key key;
@Persistent
private Op op = null;
}
When I persist, I use this code :
ExtendedOp op = new ExtendedOp();
op.addNewEntry(new Entry());
op.addNewEntry(new Entry());
pm.makePersistent(op);
After, I persisted, I reload the "ExtendedOp" with this :
String connectionQuery = "select from " + ExtendedOp.class.getName();
opArr = (List) pm.newQuery(connectionQuery).execute();
if (opArr != null) {
for (ExtendedOp opExt : opArr) {
if ( opExt.getEntryArr() != null)
for (Entry entry : sale.getEntryArr()) {
System.out.println("ok"); //works!
if (entry.getOp() != null)
System.out.println("perfect"); //never
display
}
}
}
The problem is : the Entry has the field "operation" always null. This
field is from the relation one-to-many. Maybe this field is still null
because is class type is "parent" of ExtendedOp?
Could you help me to solve that problem?
Thanks you very much,
Bat
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