Re: Get PK value of a previously generated object

From: mr.abanjo (mr.abanj..mail.com)
Date: Tue Aug 10 2010 - 11:37:11 UTC

  • Next message: Andrus Adamchik: "Re: Get PK value of a previously generated object"

    Hi,
    in the meanwhile i tried to map the relation between the two objects, but
    when i commit i receive this error:

    Exception in thread "main" java.lang.IndexOutOfBoundsException: Index: 0,
    Size: 0
    at java.util.ArrayList.RangeCheck(Unknown Source)
    at java.util.ArrayList.get(Unknown Source)
    at java.util.Collections$UnmodifiableList.get(Unknown Source)
    at
    org.apache.cayenne.map.ObjRelationship.isToDependentEntity(ObjRelationship.java:259)
    at
    org.apache.cayenne.map.ObjRelationship.isSourceIndependentFromTargetChange(ObjRelationship.java:252)
    at
    org.apache.cayenne.CayenneDataObject.validateForSave(CayenneDataObject.java:587)
    at
    org.apache.cayenne.CayenneDataObject.validateForInsert(CayenneDataObject.java:658)
    at
    org.apache.cayenne.access.ObjectStoreGraphDiff.validateAndCheckNoop(ObjectStoreGraphDiff.java:100)
    at
    org.apache.cayenne.access.DataContext.flushToParent(DataContext.java:1217)
    at
    org.apache.cayenne.access.DataContext.commitChanges(DataContext.java:1138)

    I think that the error is located at this line:

    public boolean isToDependentEntity() {
          return ((DbRelationship)
    getDbRelationships().get(0)).isToDependentPK();
    }

    ..seems that cayenne don't know the relation but i've configured it in a
    datamap:

    <db-relationship name="relationname" source="ChildDBEntity"
    target="MainDBEntity" toMany="false">
    <db-attribute-pair source="mainid" target="id"/>
    </db-relationship>
    <obj-relationship name="relationname" source="ChildOBJEntity"
    target="MainOBJEntity" deleteRule="Nullify"
    db-relationship-path="relationname"/>

    Thanks for any support.

    Davide

    On Tue, Aug 10, 2010 at 10:46 AM, mr.abanjo <mr.abanj..mail.com> wrote:

    > Hi Mike,
    > if i understand correctly i must configure in cayenne datamap xml file the
    > relation between the two objects, and than declare an attribute in the main
    > object that contains the "child".
    > I know that this is the best way ( if i want to model a database the
    > relations must be declared ) but why with the DataObjectUtils i don't
    > receive the value?
    > There is something i do in a wrong way?
    >
    > Thanks
    > Davide
    >
    > P.S. I wrote this code in a wrong way in my previous email :
    >
    > DataContext...registerNewObject(MainObject);
    >
    > Obviously the "MainObject" is the isntance and not the class :-)
    >
    >
    >
    >
    > On Mon, Aug 9, 2010 at 6:18 PM, Mike Kienenberger <mkienen..mail.com>wrote:
    >
    >> It's actually much easier than that.
    >>
    >>
    >> // Create main object
    >> // Create child object
    >>
    >> mainObj.setChild(childObj);
    >>
    >> This will automatically set the correct PK and FK values.
    >>
    >> You can also commit both changes at the same time rather than separately.
    >>
    >> On Mon, Aug 9, 2010 at 12:11 PM, mr.abanjo <mr.abanj..mail.com> wrote:
    >> > Hi,
    >> > my application need to generate a "parent" object and then create a
    >> "child"
    >> > object that contains the PK value of the parent.
    >> > I'm using MySQL and the colum "id" is "autoincrement". ( both tables )
    >> >
    >> > So first i create the main object (it extends DataObject ):
    >> >
    >> > MainObject mainObj = new MainObject();
    >> > //setting properties... without id.. it's generated by mysql
    >> > mainObj.set......
    >> > ....
    >> > ...
    >> > DataContext...registerNewObject(MainObject);
    >> > DataContext...commitChanges();
    >> >
    >> > The record is succesfully inserted in the database!
    >> >
    >> > Then i need to get the PK... in this case a single column ( Long ).
    >> >
    >> > If i insepct the corresponding filed it is empty, so i see in the
    >> > documentation that there are two ways to perform this task:
    >> > http://cayenne.apache.org/doc30/accessing-pk-and-fk-values.html
    >> > public Long getMainObjectId() {
    >> > return (getObjectId() != null && !getObjectId().isTemporary()) ? (Long)
    >> > getObjectId().getIdSnapshot().get(ID) : null;
    >> > }
    >> >
    >> > http://cayenne.apache.org/doc30/dataobjectutils.html
    >> > long myId = (Long)DataObjectUtils.pkForObject(MainObject);
    >> >
    >> >
    >> > but, with both techniques the value returned is "null"!
    >> >
    >> > What is wrong?
    >> >
    >> > Thansk for support.
    >> >
    >> > Davide
    >> >
    >>
    >
    >

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