Re: Cross data map relationships

Andrus,

What should I do then with the entity resolver?

I created it like you said but it=E2=80=99s still not being used.

Thank you
Ricardo Parada




> On Oct 14, 2025, at 5:33=E2=80=AFPM, Andrus Adamchik <[email protected]>=
 wrote:
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> =EF=BB=BF
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>> I then save the first  data map and it throws a NullPointerException. =20=

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> Before save, try this to make sure entities can find each other across Dat=
aMaps:
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> EntityResolver namespace =3D new EntityResolver(List.of(mainMap, errorsMap=
));
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>> (I avoided creating data nodes and the project in this code to keep thing=
s simple and illustrate the NullPointerException)
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> BTW, if you have a single DataNode, don't bother creating it in the model.=
 It is much simpler and cleaner to just assign a DataSource when creating a C=
ayenneRuntime, and Cayenne will use it to handle all DataMaps in the project=
.
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> Andrus
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>> On Oct 14, 2025, at 5:23=E2=80=AFPM, Ricardo Parada <[email protected]=
LID> wrote:
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>> Here is a very minimal test of what I am seeing.
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>> Two data maps: Main and Errors.
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>> I have an APP_USER DbTable in the Main data map and an APP_ERROR DbTable i=
n the Errors data map.
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>> Then I have a to-many relationship and inverse to one between these two.
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>> APP_USER <->> APP_ERROR
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>> I then simply create the ObjEntity, ObjAttribute and ObjRelationship obje=
cts programmatically.
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>> I then save the first  data map and it throws a NullPointerException. =20=

>>=20
>> Here is the isolated test:
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>> (I avoided creating data nodes and the project in this code to keep thing=
s simple and illustrate the NullPointerException)
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>> package play.cay.utils.conversion;
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>> import java.io.PrintWriter;
>> import java.sql.Types;
>>=20
>> import org.apache.cayenne.configuration.EmptyConfigurationNodeVisitor;
>> import org.apache.cayenne.map.DataMap;
>> import org.apache.cayenne.map.DbAttribute;
>> import org.apache.cayenne.map.DbEntity;
>> import org.apache.cayenne.map.DbJoin;
>> import org.apache.cayenne.map.DbRelationship;
>> import org.apache.cayenne.map.ObjAttribute;
>> import org.apache.cayenne.map.ObjEntity;
>> import org.apache.cayenne.map.ObjRelationship;
>> import org.apache.cayenne.util.XMLEncoder;
>>=20
>> public class DataMapTest {
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>>   public static void main(String[] args) {
>>       // Create DataMaps
>>       DataMap mainMap =3D new DataMap("Main");
>>       DataMap errorsMap =3D new DataMap("Errors");
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>>       // -------------------- DB Entities --------------------
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>>       // APP_USER DbEntity
>>       DbEntity appUserDb =3D new DbEntity("APP_USER");
>>       DbAttribute appUserIdDbAttr =3D new DbAttribute("ID", Types.INTEGER=
, appUserDb);
>>       appUserIdDbAttr.setPrimaryKey(true);
>>       appUserDb.addAttribute(appUserIdDbAttr);
>>       appUserDb.addAttribute(new DbAttribute("NAME", Types.VARCHAR, appUs=
erDb));
>>       appUserDb.addAttribute(new DbAttribute("EMAIL", Types.VARCHAR, appU=
serDb));
>>       appUserDb.getPrimaryKeyGenerator();
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>>       // APP_ERROR DbEntity
>>       DbEntity appErrorDb =3D new DbEntity("APP_ERROR");
>>       DbAttribute appErrorIdDbAttr =3D new DbAttribute("ID", Types.INTEGE=
R, appErrorDb);
>>       appErrorDb.addAttribute(appErrorIdDbAttr);
>>       appErrorDb.addAttribute(new DbAttribute("APP_USER_ID", Types.INTEGE=
R, appErrorDb));
>>       appErrorDb.addAttribute(new DbAttribute("ERROR_MESSAGE", Types.VARC=
HAR, appErrorDb));
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>>       // Add DbEntities to respective maps
>>       mainMap.addDbEntity(appUserDb);
>>       errorsMap.addDbEntity(appErrorDb);
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>>       // -------------------- DB Relationships --------------------
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>>       // APP_ERROR -> APP_USER (to-one)
>>       DbRelationship toUserRel =3D new DbRelationship("appUser");
>>       toUserRel.setSourceEntity(appErrorDb);
>>       toUserRel.setTargetEntityName(appUserDb);
>>       toUserRel.setToMany(false);
>>       toUserRel.addJoin(new DbJoin(toUserRel, "APP_USER_ID", "ID"));
>>       appErrorDb.addRelationship(toUserRel);
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>>       // APP_USER ->> APP_ERROR (to-many)
>>       DbRelationship errorsRel =3D new DbRelationship("errors");
>>       errorsRel.setSourceEntity(appUserDb);
>>       errorsRel.setTargetEntityName(appErrorDb);
>>       errorsRel.setToMany(true);
>>       errorsRel.addJoin(new DbJoin(errorsRel, "ID", "APP_USER_ID"));
>>       appUserDb.addRelationship(errorsRel);
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>>       // -------------------- ObjEntities --------------------
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>>       // APP_USER ObjEntity
>>       ObjEntity appUserObj =3D new ObjEntity("AppUser");
>>       appUserObj.setDbEntity(appUserDb);
>>       appUserObj.addAttribute(new ObjAttribute("id", "java.lang.Integer",=
 appUserObj));
>>       appUserObj.addAttribute(new ObjAttribute("name", "java.lang.String"=
, appUserObj));
>>       appUserObj.addAttribute(new ObjAttribute("email", "java.lang.String=
", appUserObj));
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>>       // APP_ERROR ObjEntity
>>       ObjEntity appErrorObj =3D new ObjEntity("AppError");
>>       appErrorObj.setDbEntity(appErrorDb);
>>       appErrorObj.addAttribute(new ObjAttribute("id", "java.lang.Integer"=
, appErrorObj));
>>       appErrorObj.addAttribute(new ObjAttribute("errorMessage", "java.lan=
g.String", appErrorObj));
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>>       // Add ObjEntities to respective maps
>>       mainMap.addObjEntity(appUserObj);
>>       errorsMap.addObjEntity(appErrorObj);
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>>       // -------------------- ObjRelationships --------------------
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>>       // AppError =C3=A2=C2=86=C2=92 AppUser (to-one)
>>       ObjRelationship appUserRel =3D new ObjRelationship("appUser");
>>       appUserRel.setSourceEntity(appErrorObj);
>>       appUserRel.setTargetEntityName(appUserObj); // sets target name
>>       appUserRel.setDbRelationshipPath("appUser");
>>       appErrorObj.addRelationship(appUserRel);
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>>       // AppUser =C3=A2=C2=86=C2=92 AppError (to-many)
>>       ObjRelationship errorsRelObj =3D new ObjRelationship("errors");
>>       errorsRelObj.setSourceEntity(appUserObj);
>>       errorsRelObj.setTargetEntityName(appErrorObj); // sets target name
>>       errorsRelObj.setDbRelationshipPath("errors");
>>       appUserObj.addRelationship(errorsRelObj);
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>>       PrintWriter stdout =3D new PrintWriter(System.out, true);
>>       XMLEncoder encoder =3D new XMLEncoder(stdout, "\t", "11");
>>       EmptyConfigurationNodeVisitor visitor =3D new EmptyConfigurationNod=
eVisitor();
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>>       stdout.println(mainMap.getName());
>>       stdout.println();
>>       encoder.nested(mainMap, visitor);
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>>       stdout.println();
>>       stdout.println();
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>>       stdout.println(errorsMap.getName());
>>       stdout.println();
>>       encoder.nested(errorsMap, visitor);
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>>   }
>> }
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>>>=20
>>>> On Oct 14, 2025, at 3:29=E2=80=AFPM, Ricardo Parada <[email protected]> w=
rote:
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>>> =EF=BB=BFHello,
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>>> I wrote a converter to convert our eomodels from EOF to Cayenne-project.=
xml and data maps .map.xml
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>>> So far so good. However, I seem to be running into a problem for cross d=
ata map relationships.
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>>> I=E2=80=99m using 5.0-M1.
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>>> When I=E2=80=99m creating the ObjRelationship I call:
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>>> objRel.setTargetEntityName(targetObjEntity);
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>>> If I then call objRel.getTargetEntityName() it returns the correct targe=
t entity name. =20
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>>> However, if I call objRel.getTargetEntity() it returns null.
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>>> I debugged the code and I can see that getTargetEntity() is looking for t=
he target entity name in the data map corresponding to the source ObjEntity.=
 And it does not find it and returns null for that reason.
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>>> As a result of that, when I call encodeAsXML() on objRel I see that the X=
ML is missing the target attribute in the obj-relationship xml tag.
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>>> Is this a bug in 5.0-M1 or am I missing something when creating my ObjRe=
lationship programmatically.
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>>> I could put all eomodels that have cross eomodel relationships into the s=
ame data map to avoid this problem.
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>>> But when I create it in Cayenne Modeler 4.3.3 it seems to work. I see th=
e obj-relationship in the XML have target correctly set.
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>>> Thank you all in advance.
>>> Ricardo Parada
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