Fast Object Database for Java - with JPA/JDO support

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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

Chapter 2 - JPA Entity Classes

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

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

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

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 -->

A bidirectional OneToOne association with a shared primary key

@OneToOne association that has a shared primary key, example: 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

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

Primary key generation problem after changing entity package

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

Merge failure with composite primary key

should fix it. The composite primary key issue is unclear, since switching to a single primary key

Changing Primary Key

that, and query the table all the PK fields are null or 0. What can I do to modify primary keys? Trianglehead Json Error ObjectDB doesn't support changing primary keys, as it may break references to objects

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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