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The term persistable types refers to data types that can be used for storing data in the database. ObjectDB supports all the JPA persistable types , which are: User defined classes - Entity classes, Mapped superclasses, Embeddable classes. Simple Java data types : Primitive types , Wrappers, String

classes) are represented in JPQL by the following types of expressions: Variables - FROM ... . But more often they are used in JPQL path expressions that navigate to values of simple types (number, boolean, string, date). Simple type values are more useful in queries. They have special operators

The following interfaces and enum represent types in the JPA Metamodel API:  See the Metamodel Type Interface Hierarchy section for more details and examples.

This section contains the most essential JPA types .

that Java reflection provides for general Java types . The Metamodel Interface The main interface of the JPA ... types  (which are referred to as managed types ) in the persistent object model. Three methods can be used to retrieve sets of types : // Get all the managed classes: // (entity classes

name and either the same type or a convertible type , as explained below. A matching field ... the hierarchy, removing an intermediate class in the hierarchy, etc.). Convertible Types When an old matching field is found but its type is different than the type of the new field (with the same name

This section contains miscellaneous JDO types :

-superclass attribute. identity- type and objectid-class The identity- type and objectid-class attributes ... and persistent in JDO), or a field whose declared type is java.lang.Object or some interface, but holds at runtime only values of persistent types . Specifying a none value, as demonstrated by field f1 , changes

if the field exists but its type cannot be compared with an int value, a JDOUserException is thrown ... much faster. The execute() method returns a Collection instance, but its declared return type is Object ... the candidate collection . A Query instance for this type of query can be obtained by

). 3.2  Persistent Fields and Types Storing a persistent object in the database does not ... transient , and have persistent types . Every persistent class is a persistent type . The following predefined system types are also persistent types : All the primitive types - boolean , byte , short , char