在3.3.9【字段类型之关系与引用】一文中已经描述了各种关系字段的常规写法，还有一些特殊场景如：关系映射中存在常量，或者M2M中间表是大于两个字段构成。
举例说明关系字段-高级用法
场景描述
PetTalent模型增加talentType字段，PetItem与PetTalent的多对多关系增加talentType（达人类型），PetItemRelPetTalent 中间表维护petItemId、petTalentId以及talentType，PetDogItem和PetCatItem分别重写petTalents 字段，关系中增加常量描述。示意图如下
实际操作步骤：
Step1 新增 TalentTypeEnum
package pro.shushi.pamirs.demo.api.enumeration;
import pro.shushi.pamirs.meta.annotation.Dict;
import pro.shushi.pamirs.meta.common.enmu.BaseEnum;
@Dict(dictionary = TalentTypeEnum.DICTIONARY,displayName = "达人类型")
public class TalentTypeEnum extends BaseEnum<TalentTypeEnum,Integer> {
public static final String DICTIONARY ="demo.TalentTypeEnum";
public final static TalentTypeEnum DOG =create("DOG",1,"狗达人","狗达人");
public final static TalentTypeEnum CAT =create("CAT",2,"猫达人","猫达人");
}Step2 PetTalent模型增加talentType字段
package pro.shushi.pamirs.demo.api.model;
import pro.shushi.pamirs.demo.api.enumeration.TalentTypeEnum;
import pro.shushi.pamirs.meta.annotation.Field;
import pro.shushi.pamirs.meta.annotation.Model;
@Model.model(PetTalent.MODEL_MODEL)
@Model(displayName = "宠物达人",summary="宠物达人",labelFields ={"name"})
public class PetTalent extends AbstractDemoIdModel{
public static final String MODEL_MODEL="demo.PetTalent";
@Field(displayName = "达人")
private String name;
@Field(displayName = "达人类型")
private TalentTypeEnum talentType;
}Step3 修改PetItem的petTalents字段，在关系描述中增加talentType（达人类型）
@Field.many2many(relationFields = {"petItemId"},referenceFields = {"petTalentId","talentType"},through = "PetItemRelPetTalent")
@Field.Relation(relationFields = {"id"}, referenceFields = {"id","talentType"})
@Field(displayName = "推荐达人",summary = "推荐该商品的达人们")
private List<PetTalent> petTalents;Step4 PetDogItem增加petTalents字段，重写父类PetItem的关系描述
-
talentType配置为常量，填入枚举的值
-
增加domain描述用户页面选择的时候自动过滤出特定类型的达人，RSQL用枚举的name
@Field.many2many(relationFields = {"petItemId"},referenceFields = {"petTalentId","talentType"},through = "PetItemRelPetTalent")
@Field.Relation(relationFields = {"id"}, referenceFields = {"id","talentType"})
@Field(displayName = "推荐达人",summary = "推荐该商品的达人们")
private List<PetTalent> petTalents;Step5 PetCatItem增加petTalents字段，重写父类PetItem的关系描述
-
talentType配置为常量，填入枚举的值
-
增加domain描述用户页面选择的时候自动过滤出特定类型的达人，RSQL用枚举的name
@Field(displayName = "推荐达人")
@Field.many2many(
through = "PetItemRelPetTalent",
relationFields = {"petItemId"},
referenceFields = {"petTalentId","talentType"}
)
@Field.Relation(relationFields = {"id"}, referenceFields = {"id", "#2#"}, domain = " talentType == CAT")
private List<PetTalent> petTalents;Step6 清除中间表demo_core_pet_item_rel_pet_talent的数据记录
清除PetItem与PetTalent的多对多中间表demo_core_pet_item_rel_pet_talent的数据记录
Step7 重启看效果
- 修改达人记录，选择不同达人类型
- PetItem、PetCatItem、PetDogItem不同的交互页面
Oinone社区 作者：史, 昂原创文章，如若转载，请注明出处：https://doc.oinone.top/oio4/9241.html
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