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[ODB1] Chapter 5 - JDO Connections

The PersistenShows how to use database connections and transactions in JDO. ceManagerFactory interface represents a factory of database connections. Its main role is to provide PersistenceManager instances. The PersistenceManager interface represents a database connection. Every operation on a database requires a PersistenceManager instance. The Transaction interface represents a transaction on a database. Every operation that modifies the content of the database requires an active transaction.[toc hidden:1]... connection url, ObjectDB tries to create a new, empty database at that location. This behavior is an ObjectDB extension. JDO ...

 
manual

[ODB1] Chapter 4 - JDO Metadata

Shows how to define JDO metadata for persistence capable classes.... field, "" for a java.lang.String field, empty collection, 0 size array, and so on). primary-key The ...

 
issue

[ObjectDB 2.5.5_03] Unexpected exception (Error 990)

Hello! When I run this query SELECT t FROM Unit t WHERE t.lastGeocodedPosition IS NULL OR t.lastGeocodedPosition.receiveTime < :lastGeocodedPosition.receiveTime I get the following exception: ... i.e. an internal loop, and if the the internal loop is empty for a specific Unit , that Unit is ignored. So there is a difference ...

 
issue

ArrayIndexOutOfBoundsException on flush

The following exception was thrown when my app attempted to flush an objectdb database: ... copied 4) No recovery - the database is new & empty upon startup 5) No but I'll switch this on if you think it ...

 
issue

InternalException

I'm getting a new InternalException (see below). No repeatable example as yet but will work on that and let you know as soon as we have one. If there's anything in the exception which could help us narrow down the problem please let me know. ... method on start-up (otherwise we used to get errors on empty database queries). The app also runs for a period of time before the ...

 
forum_thread

First query takes 4+ minutes to complete

Hi, we are evaluating ObjectDB 2.5.1_04 in embedded mode hoping to replace SQLite in our application. We observed that in our case it takes on average more than 4 minutes to complete the first SELECT query that we run on the DB which contains about 320,000 records of a single type of object. SQLite in comparison responds within few seconds on average with the same number of records. We hope to receive your recommendation on how to improve this result with this post.   Test System ... } ) Start with a new empty database, in order to make sure that the new index is used. With ...

 
manual

[ODB1] Chapter 7 - JDOQL Queries

Explains how to use JDOQL, the Java/JDO Query Language.... A Query instance can even be constructed by an empty newQuery() form: Query newQuery ( ) ; ...

 
forum_thread

Failover from Master to Slave

Good morning! I am interested in ObjectDB for a client project I am currently working on. In order to evaluate your tool I would like to know if your product has the ability to failover from a Master Database to a Slave Database and then recover back to the master when the master comes back online. I don't see any documentation about automatic failover.   Thanks Rich   ... Possible solution is to create a marker file (even empty) on the master server file system and on failure to delete that file and ...

 
forum_thread

Replication issue, Replayer failing due to NullPointerException.

I'm getting replication errors and upon trying to play the replayer I get a NullPointerException which i'm also seeing in the slave logs when it's trying to replicate... ... worth noting that some of the databases may be totally empty(no objects persisted) when trying to replicate. I'm going to ...

 
manual

FROM clause (JPQL / Criteria API)

Explains how to use the FROM clause and JOIN expressions in a JPA/JPQL query.... CURRENT_TIMESTAMP,DELETE, DESC, DISTINCT, ELSE, EMPTY, END, ENTRY, ESCAPE, EXISTS, FALSE, FETCH,FROM, GROUP, HAVING, IN, INDEX, ...