com.easycodebox.common.jpa

注释类型 OneToOne

@Target(value={METHOD,FIELD})
 @Retention(value=RUNTIME)
public @interface OneToOne

This annotation defines a single-valued association to another entity that has one-to-one multiplicity. It is not normally necessary to specify the associated target entity explicitly since it can usually be inferred from the type of the object being referenced.

    Example 1: One-to-one association that maps a foreign key column

    On Customer class:

    @OneToOne
    @JoinColumn(
        name="CUSTREC_ID", unique=true, nullable=false, updatable=false)
    public CustomerRecord getCustomerRecord() { return customerRecord; }

    On CustomerRecord class:

    @OneToOne(mappedBy="customerRecord")
    public Customer getCustomer() { return customer; }

    Example 2: One-to-one association that assumes both the source and target share the same primary key values. 

    On Employee class:

    @Entity
    public class Employee {
        @Id Integer id;
    
        @OneToOne @PrimaryKeyJoinColumn
        EmployeeInfo info;
        ...
    }

    On EmployeeInfo class:

    @Entity
    public class EmployeeInfo {
        @Id Integer id;
        ...
    }
 

从以下版本开始:

Java Persistence 1.0

可选元素概要

可选元素

限定符和类型	可选元素和说明
FetchType	fetch 此功能暂未实现
String	mappedBy (Optional) The field that owns the relationship.
Class	targetEntity (Optional) The entity class that is the target of the association.

元素详细资料

targetEntity

public abstract Class targetEntity

(Optional) The entity class that is the target of the association.

Defaults to the type of the field or property that stores the association.

默认值:

void.class

fetch

public abstract FetchType fetch

此功能暂未实现

默认值:

com.easycodebox.common.jpa.FetchType.LAZY

mappedBy

public abstract String mappedBy

(Optional) The field that owns the relationship. This element is only specified on the inverse (non-owning) side of the association.

默认值:

""