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265 words

javax.persistence.Basic - JPA annotation

javax.persistence
Annotation Basic

Target:
Fields (including property get methods)
The simplest type of mapping to a database column. The Basic annotation can be applied to a persistent property or instance variable of any of the following types: Java primitive types, wrappers of the primitive types, String, java.math.BigInteger, java.math.BigDecimal, java.util.Date, java.util.Calendar, java.sql.Date, java.sql.Time, java.sql.Timestamp, byte[], Byte[], char[], Character[], enums, and any other type that implements java.io.Serializable.

The use of the Basic annotation is optional for persistent fields and properties of these types. If the Basic annotation is not specified for such a field or property, the default values of the Basic annotation will apply.

Example 1:

    @Basic
    protected String name;

Example 2:

    @Basic(fetch=LAZY)
    protected String getName() { return name; }

Since:
JPA 1.0
FetchType fetch
(Optional) Defines whether the value of the field or property should be lazily loaded or must be eagerly fetched.
(Optional) Defines whether the value of the field or property should be lazily loaded or must be eagerly fetched. The EAGER strategy is a requirement on the persistence provider runtime that the value must be eagerly fetched. The LAZY strategy is a hint to the persistence provider runtime. If not specified, defaults to EAGER.
Default value:
javax.persistence.FetchType.EAGER
Since:
JPA 1.0
boolean optional
(Optional) Defines whether the value of the field or property may be null.
(Optional) Defines whether the value of the field or property may be null. This is a hint and is disregarded for primitive types; it may be used in schema generation. If not specified, defaults to true.
Default value:
true
Since:
JPA 1.0
This documentation page is derived (with some adjustments) from the open source JPA 2 RI (EclipseLink)
and is available under the terms of the Eclipse Public License, v. 1.0 and Eclipse Distribution License, v. 1.0.
Object Relational Mapping (ORM) JPA 2 providers include Hibernate, EclipseLink, TopLink, OpenJPA and DataNucleus.
Object DB is not an ORM JPA implementation but an Object Database for Java with built in JPA 2 support.