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javax.persistence Annotation Type AttributeOverride
@Retention(value=RUNTIME)
AttributeOverride
注释用于重写 Basic
(不管是显式的还是默认的)属性(或字段)或者 Id 属性(或字段)的映射。
AttributeOverride
注释可以应用于扩展了映射的超类的实体或者嵌入的字段或属性,以重写映射的超类或可嵌入类所定义的基本映射。如果没有指定 AttributeOverride
注释,则列的映射方式与原映射相同。
示例: @MappedSuperclass public class Employee { @Id protected Integer id; @Version protected Integer version; protected String address; public Integer getId() { ... } public void setId(Integer id) { ... } public String getAddress() { ... } public void setAddress(String address) { ... } } @Entity @AttributeOverride(name="address", column=@Column(name="ADDR")) public class PartTimeEmployee extends Employee { // address field mapping overridden to ADDR protected Float wage(); public Float getHourlyWage() { ... } public void setHourlyWage(Float wage) { ... } }
since |
| |
See also | javax.persistence.Embedded, javax.persistence.Embeddable, javax.persistence.MappedSuperclass |
The AttributeOverride
annotation is used to
override the mapping of a Basic
(whether explicit or
default) property or field or Id property or field.
The AttributeOverride
annotation may be
applied to an entity that extends a mapped superclass or to
an embedded field or property to override a basic mapping
defined by the mapped superclass or embeddable class. If the
AttributeOverride
annotation is not specified,
the column is mapped the same as in the original mapping.
Example: @MappedSuperclass public class Employee { @Id protected Integer id; @Version protected Integer version; protected String address; public Integer getId() { ... } public void setId(Integer id) { ... } public String getAddress() { ... } public void setAddress(String address) { ... } } @Entity @AttributeOverride(name="address", column=@Column(name="ADDR")) public class PartTimeEmployee extends Employee { // address field mapping overridden to ADDR protected Float wage(); public Float getHourlyWage() { ... } public void setHourlyWage(Float wage) { ... } }
- Since:
- Java Persistence 1.0
- See Also:
Embedded
,Embeddable
,MappedSuperclass
Required Element Summary | |
---|---|
Column |
column
(Required) The column that is being mapped to the persistent attribute. |
String |
name
(Required) The name of the property whose mapping is being overridden if property-based access is being used, or the name of the field if field-based access is used. |
Element Detail |
---|
abstract public String
name()
(必需)如果使用的是基于属性的访问,则此为映射被重写的属性名称;如果使用的是基于字段的访问,则为字段名称。
英文文档:
name
public abstract String name
- (Required) The name of the property whose mapping is being
overridden if property-based access is being used, or the
name of the field if field-based access is used.
abstract public Column
column()
(必需)映射到持久属性的列。映射类型与可嵌入类或映射超类中定义的类型保持一致。
英文文档:
column
public abstract Column column
- (Required) The column that is being mapped to the persistent
attribute. The mapping type will remain the same as is
defined in the embeddable class or mapped superclass.
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Copyright 2007 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms.
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