About fields

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Manual
230

JPA Entity Fields

Fields of persistable user defined classes (entity classes, embeddable classes and mapped superclasses) can be classified into the following five groups: Transient fields Persistent fields Inverse (Mapped By) fields Primary key (ID) fields Version field The first three groups (transient, persistent
JPA Doc
115

JPA Annotations for Fields

The way a field of a persistable class is managed by JPA can be set by the following annotations: Additional annotations (and enum) are designated for enum fields: Other additional annotations (and enum) are designated for date and calendar fields: Chapter 2 of the ObjectDB manual explains how to use all the above annotations.
JDO Doc
110

JDO Annotations for Fields

The way a field of a persistable class is managed by JDO can be set by the following annotations and enum types:
Manual
100

Database Schema Evolution

Modifications to entity classes that do not change their persistent field definitions (their schema ... and non persistent fields. However, additions, deletions and modifications to the persistent fields ... again. Conversion of an entity object to the new schema is done on a field by field basis: For every field in
Manual
66

Chapter 2 - JPA Entity Classes

Explains how to define and use JPA entity classes and other JPA persistable types.
JDO Doc
47

FetchPlan.DETACH_LOAD_FIELDS

Static Field javax.jdo.FetchPlan int DETACH_LOAD_FIELDS For use with PersistenceManager.detachCopy and setDetachmentOptions. Specifies that fields that are not loaded but are in the current fetch plan should be loaded prior to detachment. Since: JDO 2.0
JDO Doc
47

FetchPlan.DETACH_UNLOAD_FIELDS

Static Field javax.jdo.FetchPlan int DETACH_UNLOAD_FIELDS For use with PersistenceManager.detachCopy and setDetachmentOptions. Specifies that fields that are loaded but not in the current fetch plan should be unloaded prior to detachment. Since: JDO 2.0
Manual
38

Index Definition

which fields to define with indexes should be done carefully. Single Field Index JPA does not define ... } @Unique represents a unique index that prevents duplicate values in the indexed field ... field (similar to how primary keys behave). @Index represents either an ordinary index
Manual
36

Database Explorer

the database and their persistent fields and indexes. The [Query] window enables running JPQL ... , every column represents a persistent field, and the content of a cell is the value of a single field in ... and the values of its persistent fields are represented as child nodes. Tree windows provide easier
Manual
36

Retrieving JPA Entity Objects

but all its other persistent fields are uninitialized. The object content is retrieved from the database and the persistent fields are initialized, lazily, when the entity object is first accessed ... collection and map persistent fields (i.e. through one-to-one and many-to-one relationships