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Pre-detach loading: retrieval by navigation not working in if statement

-why-retrieval-by-navigation-and-access webel Dr Darren Kelly It could be some sort of JVM optimization ... system a BooleanValue wrapper is ultimately an Element that can be referenced by ID, and meets a uniform and powerful ... the whole story. webel Dr Darren Kelly By JVM optimizations I meant JIT Compiler optimizations and not

Should derived fields of an EmbeddedId be manually maintained by app code?

, of type ECompoundKeyMapItem, identified by their "key" within the EContainer class. The items ... "ECompoundKeyMapSubItem", identified by their keys. The embeddedId for the item class, ECompoundKeyMapItemId ... = parent; } [ObjectDB 2.3.0_01] Unexpected exception (Error 990) Generated by Java HotSpot(TM

Grouping by date()

hour(ov.created), count(ov) from ObjectView ov group by hour(ov.created) order by hour(ov.created) ASC ... have to group by date(). For few queries I was concatenating 'date' from year()-month()-day() calls ... . When you group by date() there are two days per day. I mean group by divides each day

Locking in JPA

update collisions resulting from simultaneous updates to the same data by two concurrent users. Locking ... by another transaction. When using ObjectDB, optimistic locking is enabled by default and fully ... is automatically increased by one. Version numbers are managed internally but can be exposed by defining a version

Removed entities can be found by query in the same transaction

Hello, we opened a transaction, load an entity from database and removed this entity by em.remove(). Afterwards the entity can be load again by query although the resulted entity have an attribute ... in build 2.7.4_04: ObjectDB uses snapshots in order to isolate transactions, i.e. to hide

Lazy loading of mapped by (inverse) singular references

ObjectDB ignores lazy setting of non collection mapped by (inverse) fields and loads them always eagerly. This is allowed by JPA since lazy is only hint but it is not efficient. The reason ... , at least as hollow objects. In order to instantiate referenced objects their exact type is needed

JPA / JDO Class Enhancer

ObjectDB Enhancer is a post compilation tool that improves performance by modifying the byte code ... (and actually required by JPA but not enforced by ObjectDB) to avoid accessing persistent fields ... . by using the get and set methods). If you follow this practice only user defined persistable classes

JPA Criteria API Queries

, count, sum, avg, min, max, ...). ORDER BY clause (orderBy, Order, asc, desc). The links ... , are defined by the instantiation of Java objects that represent query elements. A major advantage ... factory of criteria queries and criteria query elements. It can be obtained either by

[ODB1] Chapter 3 - Persistent Classes

. Only the state of the object as reflected by its persistent fields is stored. Persistent fields, by default ... dimensional arrays Some of the persistent types above are defined as optional by JDO (arrays ... . For example, the class java.awt.Image is not supported by JDO. You can store images in byte[] fields

[ODB1] Chapter 2 - A Quick Tour

by step. Both sample programs are contained in ObjectDB's samples directory. 2.1 Hello World ... ArrayList list; 18 try { 19 // Retrieve the list from the database by ... is expected to be retrieved from the database by its name "Hello World" using the getObjectById

Getting Started

ObjectDB is very easy to use. Follow the Getting Started Tutorial and the Quick Tour manual chapter and in minutes you may be able to write and run first Java programs against ObjectDB.

Prior knowledge or experience in database programming (SQL, JDBC, ORM, JPA, etc.) is not required, but some background in using the Java language is essential.

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