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https://issues.apache.org/jira/browse/CAY-2255?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Nikita Timofeev updated CAY-2255:
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Fix Version/s: 4.0.M6
> ObjectSelect improvement: columns as full entities
> --------------------------------------------------
>
> Key: CAY-2255
> URL: https://issues.apache.org/jira/browse/CAY-2255
> Project: Cayenne
> Issue Type: Improvement
> Components: Core Library
> Reporter: Nikita Timofeev
> Assignee: Nikita Timofeev
> Fix For: 4.0.M6
>
>
> *Changes in API*:
> # Add new Expression {{ASTFullObject}} that will be just a marker for the
> desired logic.
> This expression can be later (_in post 4.0 versions_) used in {{where()}}
> and in {{orderBy()}} methods to act as ObjectId and
> thus fill another gap where hacks like {{"db:OBJECT_ID"}} are used now.
> # Add new factory methods in Property:
> {code}
> <T extends Persistent> Property<T> createSelf(Class<? super T> type);
> <T extends Persistent> Property<T> createForRelationship(
> Property<?> property, Class<? super T> type)
> {code}
> # Prohibit direct usage of Properties mapped on toMany relationships, so that
> the following code will throw a {{CayenneRuntimeException}}
> {code}
> List<Object[]> result = ObjectSelect.query(Artist.class)
> .columns(Artist.ARTIST_NAME, Artist.PAINTING_ARRAY)
> .select(context);
> {code}
> *Usage examples*:
> # Selecting root object plus some related fields:
> {code}
> Property<Artist> artistSelf = Property.createSelf(Artist.class);
> List<Object[]> result = ObjectSelect.query(Artist.class)
> .columns(artistSelf, Artist.ARTIST_NAME,
> Artist.PAINTING_ARRAY.count())
> .select(context);
> {code}
> # Selecting toOne relationship:
> {code}
> List<Object[]> result = ObjectSelect.query(Painting.class)
> .columns(Painting.PAINTING_TITLE, Painting.TO_ARTIST,
> Painting.TO_GALLERY)
> .select(context);
> {code}
> # Selecting toMany relationship, the result will be as it will be in SQL query
> {code}
> Property<Artist> artist = Property.createSelf(Artist.class);
> Property<Painting> artistPainting =
> Property.createForRelationship(Artist.PAINTING_ARRAY, Painting.class);
> Property<Gallery> artistPaintingGallery =
> Artist.PAINTING_ARRAY.dot(Painting.TO_GALLERY);
> List<Object[]> result = ObjectSelect.query(Artist.class)
> .columns(artist, artistPainting, artistPaintingGallery)
> .select(context);
> {code}
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