About availability

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Pessimestic Locking doesn't release when application unexpectedly terminates.

Hi, We have several services in our app framework that we want to use a cluster singleton. Our approach to this was to use Objectdb's pessimestic locking. This seems to work, but if the owner of the current pessimestic lock abruptly quits without releasing the lock it doesn't get released.    Is there anyway the server can detect that a client (lock owner is no longer connected) and therefore release the lock ?   Thank you   Paul Newman ... note, I did some tests yesterday to calculate resource availability and I'm REALY impressed with the performance and stability of ...

 
manual

JPA Persistence Unit

Explains how to define a JPA persistence unit in the persistence.xml file. A JPA Persistence Unit is a logical grouping of user defined persistable classes (entity classes, embeddable classes and mapped superclasses) with related settings. Defining a persistence unit is optional when using ObjectDB, but required by JPA. ...

 
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explorer NullPointerException

I studied ObjectDB a few hours ago and got some problems when use explorer . I run it and right-click in 'Open local database' window,and the all the pop menu item is gray and disabled,such as ‘new database’,'new directory','cut','copy' ... if I click 'tools---oprions' before open database, the errot I got is: [2012-05-21 09:51:11 #1 explorer] java.lang.NullPointerException at com.objectdb.o.CNC.p(CNC.java:253) at com.objectdb.o.EHL.d(EHL.java:55) at com.objectdb.o.VPN.(VPN.java:60) at com.objectdb.o.OPD.(OPD.java:69) at com.objectdb.o.OPD.(OPD.java:42) #1 2012-05-21 01:22 I studied ObjectDB a few hours ago and got some problems when use explorer. I run it and right-click in & ...

 
manual

Strings in JPQL and Criteria Queries

Explains string expressions in JPQL queries, including LIKE, LOCATE, LOWER, UPPER, TRIM, CONCAT and SUBSTRING. String values may appear in JPQL queries in various forms: as  string literals - e.g. 'abc' , ''. as parameters - when string values are assigned as arguments. as  path e ...

 
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Geospatial functions

Hi, is it possible to implement geospatial functions (e.g. calculating distance between too points given latitude/longitude) ?Normally you would calculate the distance like: #1 2016-01-14 21:02 Hi, is it possible to implement geospatial functions (e.g. calculating distance between too points given ...

 
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Apparent Lazy Loading issues.

Hi, Thanks for the quick investigation. That has indeed fixed that issue. However there appear to be two more. #1 2011-12-19 06:18 Hi, Thanks for the quick investigation. That has indeed fixed that issue. However there appear to be two ...

 
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Optimization of Map Queries

hi! I am having loads and loads of occurrences of something like ((com.test.MyEntity) $1.map.get('com.test.MyEntity')).someProperty ... ((com.test.MyEntity) $1.map.get('com.test.MyEntity')).someOtherProperty .. ((com.test.MyEntity) $1.map.get('com.test.MyEntity')).someMoreProperties I need to use full qualified names for casting as well as for the map keys because same entity simple names may occur multiple times. Now I've got two questions: #1 2012-01-18 07:13 hi! I am having loads and loads of occurrences of something like ( ( com . test . ...

 
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ObjectDB Object Database Features

ObjectDB provides a rich set of features, many of them as the result of supporting the JPA and JDO APIs.... Dynamic composite database connections for high availability and fault tolerance. ...

 
forum_thread

Lazy Init / Eager / Join Fetch collection strategy ? What to choose ?

Hello, I'm doing some tests to choose the best collection fetch strategy. I have entities with many lazy collections and i don't want to load them all. In JPA / Hibernate world it exist some tests demonstrating how to choose the best strategy. For example : http://zeroturnaround.com/rebellabs/how-to-use-jpa-correctly-to-avoid-complaints-of-a-slow-application/ In this article,join fetch seems to be the right choice. What about ObjectDb ? The implementation is totally different. #1 2015-06-09 21:12 Hello, I'm doing some tests to choose the best collection fetch strategy. I have entities wit ...

 
manual

Logical Operators in JPQL and Criteria API

Explains how to use AND, OR and NOT in JPQL queries. Logical operators in JPQL and in JPA criteria queries enable composition of complex JPQL boolean expressions out of simple JPQL boolean expressions. This page covers the following topics: Logical Operators ...