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415

JPA Primary Key

Every entity object that is stored in the database has a primary key. Once assigned, the primary ... an object database, ObjectDB supports implicit object IDs, so an explicitly defined primary key is not required. But ObjectDB also supports explicit standard JPA primary keys, including composite primary
167

2.7.3_03 Erroneous "Attempt to modify a primary key of a managed object"

key of a managed object", but my application is not trying to change the primary key. (ObjectDB log ... is StringIdentity. Note that StringIdentity is defined in JDO to represent a combination of class + primary key ... + primary key is needed. This may solve the exception. Anyway, StringIdentity as a primary key field type
153

problem when primary key value is zero

and recommendations, in particular there are some primary keys with value == 0. These cause problems for objectDB, typically "JPA Unexpected argument as primary key". When using eclipselink, there is a workaround ... have a zero value in primary key column --> <property name="eclipselink.id-validation" value="NULL
152

A bidirectional OneToOne association with a shared primary key

@OneToOne association that has a shared primary key, example: http://fruzenshtein.com/bidirectional-one-to-one-primary-key-association/ Can ObjectDB support this same specific relationship ... . You can have a bidirectional one to one association, but it cannot be based on identical primary keys, i.e
151

More Efficient Primary Keys

Primary Key with two Longs b) Embedded Primary Key with two Longs c) Furthermore, as String ... engine. In both cases it is a composite primary key with the same size and structure. (b) requires ... Can you give us a recommendation as we can represent the Key (UUID) most efficient? Both in terms
149

Failed to commit transaction: Attempt to reuse an existing primary key value (613)

.RollbackException Failed to commit transaction: Attempt to reuse an existing primary key value (domain ... : Attempt to reuse an existing primary key value (domain.Pronostikoa:72) at com.objectdb.o ... to store more than one object in the database with the same primary key. Unfortunately
147

Primary key generation problem after changing entity package

keep getting errors : Attempt to reuse an existing primary key value... My primary keys are annotated
49

Chapter 2 - JPA Entity Classes

Explains how to define and use JPA entity classes and other JPA persistable types.
39

ObjectDB Object Database Features

support of the JPA and JDO APIs. Fundamental features of relational databases (e.g. primary keys, derived ... classes. Primary Keys Support of primary keys in ObjectDB is unique compared to other Objec-Oriented Databases. Primary Key Modes Hidden - primary key is automatically managed by ObjectDB with no @Id field
3

JDO Predefined ID Classes

An object ID is a combination of a persistence capable class and a primary key. It provides ... for persistence capable classes with a simple single field primary key: Object IDs are used in many ... but should not be used as the type of a primary key field in a persistence capable class. For example

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.

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