About FROM


Soft Reference Object Cache Recommendation

(Trying again.  Last post, ~50 minutes to compose, failed, possibly due to an attachment upload size limit being exceeded before the post attempt.  =(  ) ... byte[] until the JdoBlob2 object that owns it is evicted from the ObjectDB cache, such as when the JdoBlob2 gets deleted. I use ... detecting a full JVM GC, manually evict JdoBlob2s from their relevant PersistenceManager (via ... to be released? Can you see a path of strong references from a root that holds that  byte[] from being garbage collected? ...


objectdb-2.6.9_02 (with "objectdb.temp.no-enhancement-crc-check") vs. generic classes with interfaces: detailed investigation

objectdb-2.6.9_02 (with "objectdb.temp.no-enhancement-crc-check" system property) The following is a detailed report on investigation of multiple issues that have been mentioned in the following forum postings and issue reports (but please do not visit them from here now, the diagnostics there are now obsolete): - Issue #282 - ObjectDB-2.6.9: Failed to commit transaction: Failed to set numeric value of field property Element.id using reflection ... postings and issue reports (but please do not visit them from here now, the diagnostics there are now obsolete): -  Issue ... problem for another day). - All reports here are from executing the console test app from a shell/terminal window, NOT from ...



Bypass the cache: get data directly from the database.(Enum Constant of javax.persistence.CacheRetrieveMode)


GROUP BY and HAVING clauses

Explains how to use the GROUP BY and HAVING clauses in a JPA/JPQL query.... GROUP BY clause in the query execution order is after the FROM and WHERE clauses, but before the SELECT clause. When a GROUP BY clause ... (or tuples of database objects) that are generated by the FROM clause iteration and pass the WHERE clause filtering (if any) are sent to ...



Returns the parent From object from which the correlated From object has been obtained through correlation (use of a Subquery correlate method).(Method of javax.persistence.criteria.From)



Remove the given entity from the persistence context, causing a managed entity to become detached.(Method of javax.persistence.EntityManager)


substring(x, from, len)

Create an expression for substring extraction.(Method of javax.persistence.criteria.CriteriaBuilder)


refresh(entity, lockMode)

Refresh the state of the instance from the database, overwriting changes made to the entity, if any, and lock it with respect to given lock mode type.(Method of javax.persistence.EntityManager)


locate(x, pattern, from)

Create expression to locate the position of one string within another, returning position of first character if found.(Method of javax.persistence.criteria.CriteriaBuilder)



Represents a simple or compound attribute path from a bound type or collection, and is a "primitive" expression.(Interface of JPA)