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75

Soft Reference Object Cache Recommendation

limit being exceeded before the post attempt. =( ) I desire to have my persistent objects be cached ... for my application. This would use a Least Recently Used (LRU) mechanism to get rid of older objects ... [] and instruct ObjectDB to use soft reference for its Level One (L1) object data cache. I disable the L2 cache
72

Speed of queries that return many objects

objects is more than you may expect and much slower than just reading the data from the disk. Using embedded objects or report queries (which return fields rather than entity objects) may help ... , this may not help if you need all the objects in memory at once. support Support Thanks, the problem is that I
71

Entity listener - event instead of object

in updated entity. There is a problem however with accessing "old" version of object stored in ... @ElementCollection private Set<ActivityLog> activities; This way I can add events to given object without using EM to persist new object. What I want to accomplish is to log difference between new and old values
71

ClassCastException of same object type

I have ObjectDB partially working with my project. At the moment it seems to be saving objects and retrieving objects ok in the main project. However, when I make a plugin for the project, the new objects are persisted but not retrieved. I get the following error: java.lang.ClassCastException: org
16

Locking in JPA

in ObjectDB (and in JPA) is always at the database object level, i.e. each database object is locked separately. Optimistic locking is applied on transaction commit. Any database object ... is being performed on an old version of a database object, for which another update has already been committed
16

JPA Primary Key

Every entity object that is stored in the database has a primary key. Once assigned, the primary key cannot be modified. It represents the entity object as long as it exists in the database. As an object database, ObjectDB supports implicit object IDs, so an explicitly defined primary key is not
14

FROM clause (JPQL / Criteria API)

The FROM clause declares query identification variables that represent iteration over objects in ... a program, since both are used for iteration over objects. Range Variables Range variables are query identification variables that iterate over all the database objects of a specific entity class
14

new objects not available in mappedBy associations

> employees; creating a new mapped class, e.g. new Employee, won't result in this object being available in the same transaction: ie: for (Employee e : department.employee) won't include the new object ... automatically when the object is retrieved from the database again. Try to refresh the department object
1

[ODB1] Chapter 3 - Persistent Classes

. Instances of these classes that represent objects in the database are called persistent objects or persistent instances. Objects that do not represent anything in the database (including instances of persistent classes that live only in memory) are called transient objects or transient instances
1

[ODB1] Chapter 5 - JDO Connections

storing, retrieving, updating and deleting database objects, are provided in the next chapter (Chapter ... your application JDO portable these objects are accessed through the standard JDO interfaces. Obtaining ... PersistenceManager instance, in any context, to return its associate Transaction object. The strong

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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