ObjectDB ObjectDB

Internal Website Search

191-200 of 200 resultsRefresh


this API in order to work around the fact that Java generics are not compatible with varags ... Predicate isNotEmpty( Expression<C> collection) Create a predicate that tests whether a collection is not empty. Create a predicate that tests whether a collection is not empty. Parameters: collection

JPA Lifecycle Events

and any access level (public, protected, package and private) but should not be static. The annotation ... that fires the entity lifecycle event (which is still in progress) callback methods should not call EntityManager or Query methods and should not access any other entity objects. If a callback method

Storing JPA Entity Objects

is committed. An IllegalArgumentException is thrown by persist if the argument is not an instance ... , the referenced Address instance is not stored in the database automatically with the referencing Employee ... another entity object that is not expected to be stored in the database at the end of that transaction

Is ObjectDB better than competing object databases?

Naturally, this is not the place to look for an unbiased answer for this question ... databases do not support user defined primary keys, even though this is very useful in ... that an essential feature is missing. For example, some competing products do not support aggregate

Index Definition

which fields to define with indexes should be done carefully. Single Field Index JPA does not define ... can only be defined on ordinary persistent fields (not on primary key / version fields). Composite Index ... the lexicographic order of the words and is not ordered by the length of the words. The bottom line

Auto Generated Values

allocation will not be used. Therefore, this strategy does not guarantee there will be no gaps in ... a sequence using a table to support this strategy. ObjectDB does not have tables, so the TABLE and SEQUENCE

Defining a JPA Entity Class

Entity Classes Storing an entity object in the database does not store methods and code ... field that is not declared as static or transient is a persistent field. For example ... supports implicit object IDs, so an explicitly defined primary key is not required. On the other hand

JPA Metamodel API

(); If managed classes are not listed in the persistence unit (which is optional when using ObjectDB ... can also be used with types that are still unknown to ObjectDB (not listed in the persistence unit and have not been used yet). In this case, calling the method introduces the specified type to ObjectDB


the database, UPDATE queries do not retrieve data from the database, but when executed, update ... with the database. For example, the EntityManager may not be aware that a cached entity object in ... name) for iteration. Multiple variables and JOIN are not supported. The SET clause defines one or


if a transaction is not active. If a datastore transaction is active, this method verifies the consistency ... if flush were called, but it is not required to do so. If an optimistic transaction is active, this method ... of the instance persistent, the closure of the instance is not deleted from the data store. This method

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.

Need Help?

  1. Search ObjectDB website
  2. Read the FAQ
  3. Follow the Tutorials
  4. View or post in the forum
  5. Search or file an issue
  6. Contact support