Golang Gorm实现自定义多态模型关联查询
目录
- 一、表结构
- 二、接口定义
- 三、模型定义并实现接口
- 四、创建loader预加载器
- 五、注册loader预加载器服务
- 六、实现LoadAble通用的加载函数
- 七、调试
一、表结构
CREATE TABLE `orders` ( `id` int unsigned NOT NULL AUTO_INCREMENT, `order_no` varchar(32) NOT NULL DEFAULT '', `orderable_id` int unsigned NOT NULL DEFAULT '0', `orderable_type` char(30) NOT NULL DEFAULT '', `status` tinyint unsigned NOT NULL DEFAULT '0', `created_at` datetime NOT NULL, `updated_at` datetime NOT NULL, `deleted_at` datetime DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci; CREATE TABLE `phone` ( `id` int unsigned NOT NULL AUTO_INCREMENT, `phone_name` varchar(50) NOT NULL DEFAULT '', `phone_model` varchar(30) NOT NULL DEFAULT '', `status` tinyint unsigned NOT NULL DEFAULT '0', `created_at` datetime NOT NULL, `updated_at` datetime NOT NULL, `deleted_at` datetime DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=1003 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci; CREATE TABLE `cars` ( `id` int unsigned NOT NULL AUTO_INCREMENT, `car_name` varchar(50) NOT NULL DEFAULT '', `car_model` varchar(30) NOT NULL DEFAULT '', `status` tinyint unsigned NOT NULL DEFAULT '0', `created_at` datetime NOT NULL, `updated_at` datetime NOT NULL, `deleted_at` datetime DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=1003 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;
二、接口定义
// LoaderAble 接口定义数据加载行为 type LoaderAble interface { LoadAble(IDs []int) (map[int]any, error) } // LoadAbleItem 接口定义了可加载项的通用方法 type LoadAbleItem interface { GetAbleType() string // 获取类型键值 GetAbleID() int // 获取ID SetLoadedAbleData(data any) // 设置加载的数据 }
三、模型定义并实现接口
type Order struct { Id int `json:"id"` OrderNo string `json:"order_no"` OrderableId int `json:"orderable_id"` OrderableType string `json:"orderable_type"` Orderable any `json:"orderable" gorm:"-"` Status uint8 `json:"status"` CreatedAt *time.Time `json:"created_at"` UpdatedAt *time.Time `json:"updated_at"` DeletedAt gorm.DeletedAt `json:"deleted_at"` } func (tb *Order) TableName() string { return "orders" } func (tb *Order) GetAbleType() string { return tb.OrderableType } func (tb *Order) GetAbleID() int { return tb.OrderableId } func (tb *Order) SetLoadedAbleData(data any) { tb.Orderable = data } //--------------------------------------分割线-------------------------------------- type Car struct { Id int `json:"id"` CarName string `json:"car_name"` CarModel string `json:"car_model"` Status uint8 `json:"status"` CreatedAt *time.Time `json:"created_at"` UpdatedAt *time.Time `json:"updated_at"` DeletedAt gorm.DeletedAt `json:"deleted_at"` } func (tb *Car) TableName() string { return "cars" } // CarLoaderAble 实现 Loader 接口 type CarLoaderAble struct{} // LoadAble 具体实现加载多态关联逻辑 // IDs 多态关联类型ID(主要参数) func (loader *CarLoaderAble) LoadAble(IDs []int) (resultMap map[int]any, err error) { IDsLen := len(IDs) if IDsLen == 0 { return } car := make([]*Car, 0, IDsLen) err = mysql.DefaultMysql.Db.Debug().Where("id IN (?) AND status = ?", IDs, 1).Find(&car).Error if err != nil { return } resultMap = make(map[int]any, IDsLen) for _, item := range car { resultMap[item.Id] = item } return } //--------------------------------------分割线-------------------------------------- type Phone struct { Id int `json:"id"` PhoneName string `json:"phone_name"` PhoneModel string `json:"phone_model"` Status uint8 `json:"status" gorm:"column:status"` StatusNew uint8 `json:"status_new" gorm:"-"` CreatedAt *time.Time `json:"created_at"` UpdatedAt *time.Time `json:"updated_at"` DeletedAt gorm.DeletedAt `json:"deleted_at"` } func (tb *Phone) TableName() string { return "phone" } func (tb *Phone) AfterFind(tx *gorm.DB) (err error) { tb.StatusNew = tb.Status return } // PhoneLoaderAble 实现 Loader 接口 type PhoneLoaderAble struct{} // LoadAble 具体实现加载多态关联逻辑 // IDs 多态关联类型ID(主要参数) func (loader *PhoneLoaderAble) LoadAble(IDs []int) (resultMap map[int]any, err error) { IDsLen := len(IDs) if IDsLen == 0 { return } phone := make([]*Phone, 0, IDsLen) err = mysql.DefaultMysql.Db.Debug().Where("id IN (?) AND status = ?", IDs, 1).Find(&phone).Error if err != nil { return } resultMap = make(map[int]any, IDsLen) for _, item := range phone { resultMap[item.Id] = item } return }
四、创建loader预加载器
// LoaderAbleFactory 用于管理不同类型的加载器 type LoaderAbleFactory struct { loaders map[string]LoaderAble } func NewLoaderAbleFactory() *LoaderAbleFactory { return &LoaderAbleFactory{ loaders: make(map[string]LoaderAble), } } func (f *LoaderAbleFactory) Regwww.devze.comisterLoader(typeName string, loader LoaderAble) { f.loaders[typeName] = loader }
五、注册loader预加载器服务
var ( loaderAbleFactory *LoaderAbleFactory ) // init 选择在项目启动初始化时进行全局加载 func init() { loaderAbleFactory = NewLoaderAbleFactory() loaderAbleFactory.RegisterLoader("phone", &PhoneLoaderAble{}) loaderAbleFactory.RegisterLoader("car", &CarLoaderAble{}) log.Println("多态模型关系注册成功...") }
六、实现LoadAble通用的加载函数
// LoadAble 通用的加载函数,可以处理任何实现了 LoadableItem 接口的切片 func LoadAble[T LoadAbleItem](items []T) error { if len(items) == 0 { return nil } // 按类型分组收集ID typeIDsMap := make(map[string][]int) for _, item := range items { typeKey := item.GetAbleType() typeIDsMap[typeKey] = append(typeIDsMap[typeKey], item.GetAblephpID()) } // 使用对应的loader加载数据 typeDataMap := make(map[string]map[int]any) for typeName, ids := range typeIDsMap { loader, ok := loaderAbleFactory.loaders[typeName] if !ok { continue } resultMap, err := loader.LoadAble(ids) if err != nil { return err } typeDataMap[typeName] = resultMap } // 填充数据 for _, item := range items { if dataMap, ok := typeDataMap[item.GetAbleType()]; ok { if data, exists := dataMap[item.GetAbleID()]; exists { item.SetLoadedAbleData(data) } } } return nil }
七、调试
- 准备数据
--orders表 INSERT INTO `orders` (`id`, `order_no`, `orderable_id`, `orderable_type`, `status`, `created_at`, `updated_at`, `deleted_at`) VALUES (1, '202411010001', 1002, 'car', 1, '2024-11-01 12:03:03', '2024-11-01 12:03:06', NULL); INSERT INTO `orders` (`id`, `order_no`, `orderable_id`, `orderable_type`, `status`, `created_at`, `updated_at`, `deleted_at`) VALUES (2, '202411010002', 1001, 'phone', 1, '2024-11-01 12:03:03', '2024-11-01 12:03:06', NULL); INSERT INTO `orders` (`id`, `order_no`, `orderable_id`, `orderable_type`, `status`, `created_at`, `updated_at`, `deleted_at`) VALUES (3, '202411010003', 1000, 'car', 1, '2024-11-01 12:03:03', '2024-11-01 12:03:06', NULL); INSERT INTO `orders` (`id`, `order_no`, `orderable_id`, `orderable_type`, `status`, `created_at`, `updated_at`, `deleted_at`) VALUES (4, '202411010004', 1001, 'car', 1, '2024-11-01 12:03:03', '2024-11-01 12:03:06', NULL); INSERT INTO `orders` (`id`, `order_no`, `orderable_id`, `orderable_type`, `status`, `created_at`, `updated_at`, `deleted_at`) VALUES (5, '202411010005', 1002, 'phone', 1, '2024-11-01 12:03:03', '2024-11-01 12:03:06', NULL); --phone表 INSERT INTO `phone` (`id`, `phone_name`, `phone_model`, `status`, `created_at`, `updated_at`, `deleted_at`) VALUES (1000, 'XiaoMi', '2S', 2, '2024-11-01 11:59:37', '2024-11-01 11:59:40', NULL); INSERT INTO `phone` (`id`, `phone_name`, `phone_model`, `status`, `created_at`, `updated_at`, `deleted_at`) VALUES (1001, 'HUAWEI', 'mate60', 1, '2024-11-01 11:59:54', '2024-11-01 11:59:57', NULL); INSERT INTO `phone` (`id`, `phone_name`, `www.devze.comphone_model`, `status`, `created_at`, `updated_at`, `deleted_at`) VALUES (1002, 'Apple', 'iPhone 12 Pro Max', 1, '2024-11-01 12:00:26', '2024-11-01 12:00:28', NULL); --cars表 INSERT INTO `cars` (`id`, `car_name`, `car_model`, `status`, `created_at`, `updated_at`, `deleted_at`) VALUES (1000, '奥迪', 'A6L', 1, '2024-11-01 11:57:53', '2024-11-01 11:57:55', NULL); INSERT INTO `cars` (`id`, `car_name`, `car_model`, `status`, `created_at`, `updated_at`, `deleted_at`) VALUES (1001, '宝马', '5系', 1, '2024-11-01 11:58:12', '2024-11-01 11:58:15', NULL); INSERT INTO `cars` (`id`, `car_name`, `car_model`, `status`, `created_at`, `updated_at`, `deleted_at`) VALUES (1002, '奔驰', 'E300', 1, '2024-11-01 11:58:53', '2024-11-01 11:58:56', NULL);
- 编写代码
// Gin框架+Gorm为例 api.GET("/orders", controller.GetOrderList) // GetOrderList 获取订单列表接口 func GetOrderList(c *gin.Context) { orders := make([]*model.Order, 0) err := mysql.DefaultMysql.Db.Debug().Find(&orders).Error if err != nil { c.JSON(200, gin.H{"error": err.Error()}) return } err = model.LoadAble(orders) if err != nil { c.JSON(200, gin.H{"error": err.Error()}) return } c.JSON(200, gin.H{"data": orders}) }
- 发起请求
curl '127.0.0.1:16888/api/orders'
{ "data": [ { "id": 1, "order_no": "202411010001", "orderable_id": 1002, "orderable_type": "car", "orderable": { "id": 1002, "car_name": "奔驰", "car_model": "E300", "status": 1, "created_at": "2024-11-01T11:58:53+08:00", "updated_at": "2024-11-01T11:58:56+08:00", "deleted_at": null }, "status": 1python, "created_at": "2024-11-01T12:03:03+08:00", "updated_at": "2024-11-01T12:03:06+08:00", "deleted_at": null }, { "id": 2, "order_no": "202411010002", "orderable_id": 1001, "orderable_type": "phone", "orderable": { "id": 1001, "phone_name": "HUAWEI", "phone_model": "mate60", "status": 1, "status_new": 1, "created_at": "2024-11-01T11:59:54+08:00", "updated_at": "2024-11-01T11:59:57+08:00", "deleted_at": null }, "status": 1, "created_at": "2024-11-01T12:03:03+08:00", "updated_at": "2024-11-01T12:03:06+08:00", "deleted_at": null }, { "id": 3, "order_no": "202411010003", "orderable_id": 1000, "orderable_type": "car", "orderable": { "id": 1000, "car_name": "奥迪", "car_model": "A6L", "status": 1, "created_at": "2024-11-01T11:57:53+08:00", "updated_at": "2024-11-01T11:57:55+08:00", "deleted_at": null }, "status": 1, "created_at": "2024-11-01T12:03:03+08:00", "updated_at": "2024-11-01T12:03:06+08:00", "deleted_at": null }, { "id": 4, "order_no": "202411010004", "orderable_id": 1001, "orderable_type": "car", "orderable": { "id": 1001, php "car_name": "宝马", "car_model": "5系", "status": 1, "created_at": "2024-11-01T11:58:12+08:00", "updated_at": "2024-11-01T11:58:15+08:00", "deleted_at": null }, "status": 1, "created_at": "2024-11-01T12:03:03+08:00", "updated_at": "2024-11-01T12:03:06+08:00", "deleted_at": null }, { "id": 5, "order_no": "202411010005", "orderable_id": 1002, "orderable_type": "phone", "orderable": { "id": 1002, "phone_name": "Apple", "phone_model": "iPhone 12 Pro Max", "status": 1, "status_new": 1, "created_at": "2024-11-01T12:00:26+08:00", "updated_at": "2024-11-01T12:00:28+08:00", "deleted_at": null }, "status": 1, "created_at": "2024-11-01T12:03:03+08:00", "updated_at": "2024-11-01T12:03:06+08:00", "deleted_at": null } ] }
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