About Index
Index Definition
Describes how to define indexes in JPA entity classes and explains how indexes are used in JPQL queries.... queries over millions of objects can be executed quickly. Index management introduces overhead in terms of maintenance time and storage ... covers the following topics: Single Field Index Composite Index Multi Part Path Index ...
possible index required for improving query performance
Hi, I have the following entity class: @Entity @Table @Indices({ @Index(members={"relationshipType", "party"}), @Index(members={"relationshipType", "otherParty"}), @Index(members={"relationshipType"}) }) @XmlRootElement public class Relationship implements Comparable<Relationship> { ... Table @ Indices ( { @ Index ( members = { "relationshipType" , "party" } ) , @ Index ( members = { "relationshipType" , "otherParty" } ) , @ Index ( members = { "relationshipType" } ...
WHERE clause (JPQL / Criteria API)
Explains how to use the WHERE clause in a JPQL query.... FROM and the SELECT clauses. Practically, if a proper index is available , filtering is done earlier during FROM iteration. In the above population query, if an index is defined on the population field ObjectDB can use that index to ...
Mysterious "Attempt to persist a reference to a non managed instance" error
I've been working with ObjectDB for the past several months, and it's behaved pretty much as expected. I made a few modifications to a working set of classes today, and it's started throwing exceptions at commit time. I've stripped it down to a set of files that seem to be of trivial complexity, but it's still failing. It involves two entities, Index and Ostrich. The thing to note is that the Index structure is recursive through maps; but that's never caused any problem for me in the past. ... it's still failing. It involves two entities, Index and Ostrich. The thing to note is that the Index structure is recursive through maps; but that's never caused any ...
JDO Annotations for Index Definition
... on persistent fields: javax.jdo.annotations.Index javax.jdo.annotations.Indices ... javax.jdo.annotations.Uniques The Index Definition section of the ObjectDB manual explains these annotations ...
Chapter 2 - JPA Entity Classes
Explains how to define and use JPA entity classes and other JPA persistable types.... JPA Primary Key Auto Generated Values Index Definition Database Schema Evolution JPA Persistence Unit ...
Is ObjectDB scalable? What are its limitation?
ObjectDB is highly scalable and can manage efficiently databases in a wide range of sizes, from a few Kilobytes to hundreds of Gigabytes and even Terabytes. ObjectDB can be used in small embedded single user applications as well as in heavy loaded mu ...
JPA Primary Key
Explains how to define and use primary keys in JPA, including composite and embedded primary keys. 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 o ...
JPA query of a Set of terms
Hi, Is it possible to write a JPA query to select objects that contain a collection of elements? For example, suppose I have a table that maps a search terms to pages: @Entity public class SearchIndex { @Index SearchTerm term; @Index Page page; } Now suppose I have an array of SearchTerm objects. ie. ... public class SearchIndex { @ Index SearchTerm term ; @ Index Page page ; } Now suppose I have an array of ...
