java - Hibernate:指定父实体 中的哪一列应该使用

Question

我的 HBM 文件中有以下实体:

<join table="v_price_change_current_prices" fetch="join" inverse="true">
    <key column="product_color_id" />
    <property name="oldMSRP" column="msrp" />
    <property name="oldList"  column="list" />
</join>

我的 PRICE_CHANGE 表有一个 ID 列(主键)和一个 PRODUCT_COLOR_ID 列。

我希望 SQL Hibernate 生成将 V_PRICE_CHANGE_CURRENT_PRICES 加入到 PRICE_CHANGE.PRODUCT_COLOR_ID，如下所示:

    SELECT * from PRICE_CHANGE a, V_PRICE_CHANGE_CURRENT_PRICES b 
where a.product_color_id=b.product_color_id

但它加入到 PRICE_CHANGE.ID 代替

    SELECT * from PRICE_CHANGE a, V_PRICE_CHANGE_CURRENT_PRICES b 
where a.product_color_id=b.product_color_id

有没有办法告诉元素使用 PRICE_CHANGE.PRODUCT_COLOR_ID 而不是 PRICE_CHANGE.ID？

Answer 1

根据文档，这可能可以使用 property-ref 来实现。在 <key>元素:

5.1.21. Key

The <key> element has featured a few times within this guide. It appears anywhere the parent mapping element defines a join to a new table that references the primary key of the original table. It also defines the foreign key in the joined table:

<key
        column="columnname"                      (1)
        on-delete="noaction|cascade"             (2)
        property-ref="propertyName"              (3)
        not-null="true|false"                    (4)
        update="true|false"                      (5)
        unique="true|false"                      (6)
/>

1. column (optional): the name of the foreign key column. This can also be specified by nested element(s).
2. on-delete (optional - defaults to noaction): specifies whether the foreign key constraint has database-level cascade delete enabled.
3. property-ref (optional): specifies that the foreign key refers to columns that are not the primary key of the original table. It is provided for legacy data.
4. not-null (optional): specifies that the foreign key columns are not nullable. This is implied whenever the foreign key is also part of the primary key.
5. update (optional): specifies that the foreign key should never be updated. This is implied whenever the foreign key is also part of the primary key.
6. unique (optional): specifies that the foreign key should have a unique constraint. This is implied whenever the foreign key is also the primary key.

但我不确定这是否真的实现了(见 HHH-551 ， HHH-1829 )。

如果您真的不想使用共享主键，另一种选择是使用组合和“真实” one-to-one协会代替。

引用

Hibernate 核心引用文档

5.1.13. One-to-one

5.1.20. "Join"

5.1.21. Key