java - 如何将两个类 JPA 映射到按类型列区分的同一个表，并让它们具有一个集合，该集合是表的行

Question

假设我有这个数据库表设计（键值必须是动态的，所以不，我不能将它们变成单独的列或属性）：

餐桌屋，包括：

• ID
• 其他无关紧要的属性，例如名称等

表 house_properties 包括：

• ID
• house_id (fk 指向房子)
• 类型（枚举（'外部'，'内部'，...其他））
• 键（字符串）
• 值（字符串）

示例数据：

屋：

• id = 1, name = "随便"
• id = 2, name = "我不在乎这只是示例"

房屋属性：

• id = 100，house_id = 1，type = EXTERIOR，key = 'roof'，value = 'shingles'
• id = 101，house_id = 1，type = EXTERIOR，key = 'paint color'，value = 'white'
• id = 102，house_id = 1，类型 = EXTERIOR，键 = '百叶窗'，值 = '橙色'
• id = 103, house_id = 1, type = INTERIOR, key = '走廊墙壁颜色', value = '绿色'
• id = 104, house_id = 1, type = INTERIOR, key = '厨房地板颜色', value = '蓝色'
• id = 105, house_id = 1, type = INTERIOR, key = '浴室有镜子', value = 'false'

---

• id = 106，house_id = 2，类型 = EXTERIOR，键 = '屋顶'，值 = '金属'
• id = 107，house_id = 2，type = EXTERIOR，key = 'walls'，value = 'brick'
• id = 108, house_id = 2, type = EXTERIOR, key = 'windows', value = '双层玻璃'
• id = 109, house_id = 2, type = INTERIOR, key = '墙壁颜色', value = '红色'
• id = 110，house_id = 2，type = INTERIOR，key = '厨房地板'，value = 'lenolium'
• id = 110, house_id = 2, type = INTERIOR, key = '浴室有镜子', value = 'true'

我需要将结果属性表映射到由表的“类型”属性值确定的多个类。每个类都应该包含一组键值对。

房子很简单，但我正在尝试找出其他两个类：

@Entity
public class House {

    Integer id;

    @OneToMany(mappedBy = "house")
    Collection<ExteriorProperties> exteriorProperties;

    @OneToMany(mappedBy = "house")
    Collection<InteriorProperties> interiorProperties;

    // ... more fields
    // ... getters setters

}

// SINGLE instance for ALL house_properties rows with the same house_id and type = "EXTERIOR"
// How to JPA-map this??
public class ExteriorProperties {

    Integer id;

    @JoinColumn(name = "house_id", referencedColumnName = "id")
    @ManyToOne
    House house; // ref back to house 

    // the collection of key-value pairs that are in all rows with the same house_id and type = "EXTERIOR"
    // How to JPA map this???
    Map<String, String> properties;

    // ... getters, setters
}

// SINGLE instance for ALL house_properties rows with the same house_id and type = "INTERIOR"
// How to JPA-map this??
public class InteriorProperties {

    Integer id;

    @JoinColumn(name = "house_id", referencedColumnName = "id")
    @ManyToOne
    House house; // ref back to house 

    // the collection of key-value pairs that are in all rows with the same house_id and type = "INTERIOR"
    // How to JPA map this???
    Map<String, String> properties;

    // ... getters, setters
}

标签： javajpa