Hibernate Annotation
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2022-03-02 13:49:43
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单项one-to-one关联
@OneToOne
public @interface OneToOne
{
Class targetEntity() default void.class;
CascadeType[] cascade() default{};
FetchType fetch() default EAGER;
boolean optional() default true;
String mappedBy() default "";
}
关联方法:
1..................
@OneToOne(cascade = {CascadeType.ALL})
@JoinColumn(name = "ADDRESS_ID")
当使用复合主键的时候用@JoinColumns注解,如果不是主键则用referencedColumnName = ?
其中对于@JoinColumn
public @interface JoinColumn
{
String name() default "";
String referencedColumnName() default "";
boolean unique() default false;
boolean nullable() default true;
boolean insertable() default true;
boolean updatable() default true;
String columnDefinition() default "";
String table() default "";
}
其中对于@JoinColumns
public @interface JoinColumns
{
JoinColumn[] value();
}
2...................
public @interface PrimaryKeyJoinColumn
{
String name() default "";
String referencedColumnName() default "";
String columnDefinition() default "";
}
如果是复合主键就用@PrimaryKeyJoinColumns
public @interface PrimaryKeyJoinColumns
{
PrimaryKeyJoinColumn[] value();
}
单向One-to-Many关联
public @interface OneToMany
{
Class targetEntity() default void.class;
CascadeType[] cascade() default {};
FetchType fetch() default LAZY;
String mappedBy() default "";
}
特别注意:这里fetch的默认属性为 LAZY
@Entity
public class Customer implements java.io.Serializable{
...
private Collection<Phone> phoneNumbers = new ArrayList<Phone>();
...
@OneToMany(cascade = {CascadeType.ALL})
@JoinColumn(name = "CUSTOMER_ID")
public Collection<Phone> getPhoneNumbers(){
return phoneNumbers;
}
public void setPhoneNumbers(Collection<Phone> phones){
this.phoneNumbers = phones;
}
}