About collection

31-40 of 200Refresh
Forum
16

Using Scala collections with ObjectDB

Hi, I cannot see that it is possible to make scala collection classes persistable within ObjectDB ... .collection._  api for it to work ? (http://www.scala-lang.org/docu/files/collections-api/collections.html)   /Peter   You are right - Scala collections require some special handling, which is not
Forum
16

collection of embedded objects

1. In general, are there any restrictions of the use of @Embedded objects in collections, compared to @Entity? 2. If you have a large nested collection of @Embedded objects, and you remove the parent @Entity, does the remove cascade through the whole collection? 3. Is searching through collections
Forum
16

Custom collection types

Hi   In our project in few places there are used collections from emf framework eg EcoreEMap http ... , nevertheless it causes some questions. I checked that i can easily change the type of collection between ... of this classes but only their content so I suppose that you treat collections some how differently. Can i
Forum
16

Lazy Init / Eager / Join Fetch collection strategy ? What to choose ?

Hello, I'm doing some tests to choose the best collection fetch strategy. I have entities with many lazy collections and i don't want to load them all. (depends on context) In JPA / Hibernate world ... seems to be more efficient than only fetch required collections. Can you confirm my observations ? To finish, wake
Forum
16

PersistenceManager.getObjectsById(Collection,boolean) throwing JDOException

I have a call to getObjectsById(Collection,boolean) that is throwing a JDOException the first time ... why this might occur? We're using ObjectDB 2.2.4_02. The collection being passed in is a HashSetcollection
JPA Doc
15

javax.persistence.criteria.CollectionJoin

>, FetchParent, From, Join, Path, PluralJoinCollection,E>, Selection, TupleElement The CollectionJoin interface is the type of the result of joining to a collection over an association or element collection that has been specified as a java.util.Collection. Since: JPA 2.0 Selection
JPA Doc
15

javax.persistence.criteria.CriteriaBuilder

Predicate isEmpty( Expression collection) Create a predicate that tests whether a collection is empty. Create a predicate that tests whether a collection is empty. Parameters: collection - expression ... - expression to be tested Returns: predicate Since: JPA 2.0 Predicate isMember(E elem, Expression collection
Forum
15

No clue how to query with collection

getStreet();     int getStreetNo(); } @Entity class Contact {     Collection
collection with a concatenated value of street + streetNo (if not ... that selecting the first item of a collection ain't be a good idea. now I can select the right item
Forum
15

Fetching Collections Puzzle

(which is recommended anyway to improve performance). Paul,   As posted above your collection ... to go and retrive the first element of the collection. This will only work if you are within a transaction ... from Node n left outer join fetch n.children where ....." this will also fetch your collection
Forum
15

Nested Collection Query

if a particular member exist in one of the group? Nesting a collection directly in another collection, although supported by ObjectDB, is not valid in JPA. Accordingly the JPA query language does not ... . The recommended solution is avoid collections of collections, and instead wrap the internal collection in a user defined entity or embeddable class. snoopydoghk