Question

在环回中，我已经定义了两个具有双重多对多关系的模型，如下所示：

action.json：

    {
      "name": "Action",
      "base": "PersistedModel",
      "idInjection": true,
      "options": {
        "validateUpsert": true
      },
      "properties": {
        "text": {
          "type": "string",
          "required": true
        }
      },
      "validations": [],
      "relations": {
        "benchmark": {
          "type": "hasAndBelongsToMany",
          "model": "Course",
          "foreignKey": "benchmark"
        },
        "main": {
          "type": "hasAndBelongsToMany",
          "model": "Course",
          "foreignKey": "main"
        }
      },
      "acls": [],
      "methods": {}
    }

course.json：

    {
      "name": "Course",
      "base": "TrashModel",
      "idInjection": true,
      "options": {
        "validateUpsert": true
      },
      "properties": {
        "name": {
          "type": "string",
          "required": true
        }
      },
      "validations": [],
      "relations": {
        "benchmark": {
          "type": "hasAndBelongsToMany",
          "model": "Action",
          "foreignKey": "benchmark"
        },
        "main": {
          "type": "hasAndBelongsToMany",
          "model": "Action",
          "foreignKey": "main"
        }
      },
      "acls": [],
      "methods": {}
    }

现在，当我尝试使用以下PUT请求在动作模型和课程模型之间创建关系时：

http://localhost:3000/api/courses/57331a4eeff440cb02c886ae/benchmark/rel/5731d60da2c6d238e3c3d9b3

然后，当我使用以下GET请求中包含的相关动作模型请求课程模型时：

http://localhost:3000/api/courses/57331a4eeff440cb02c886ae?filter=%7B%22include%22%3A%5B%22benchmark%22%2C%22main%22%5D%7D

我明白了：

    {
      "name": "Introduction Lessons",
      "id": "57331a4eeff440cb02c886ae",
      "benchmark": [{
        "text": "text here",
        "id": "5731d60da2c6d238e3c3d9b3"
      }],
      "main": [{
        "text": "text here",
        "id": "5731d60da2c6d238e3c3d9b3"
      }]
    }

显然，行动现在通过基准作为主要关系附加。这怎么发生的？我的模型设置错了吗？

Answer 1

根据我的理解，当你使用hasAndBelongsToMany relashionship时，loopback会使用一个自动为你管理的直通表。

我相信默认情况下它会调用自己From_modelTo_model。为了有两个这样的重新关系，你需要告诉loopback以不同的方式管理它，否则他们使用相同的通过表。

尝试通过选项，例如

动作

"benchmark": {
  "type": "hasAndBelongsToMany",
  "model": "Course",
  "foreignKey": "benchmark",
  "through":"ActionCourseBenchmark"
},
"main": {
  "type": "hasAndBelongsToMany",
  "model": "Course",
  "foreignKey": "main",
  "through":"ActionCourseMain"
}

场

"benchmark": {
  "type": "hasAndBelongsToMany",
  "model": "Action",
  "foreignKey": "benchmark",
  "through":"ActionCourseBenchmark"
},
"main": {
  "type": "hasAndBelongsToMany",
  "model": "Action",
  "foreignKey": "main",
  "through":"ActionCourseMain"
}

有关详细信息，请参阅this github issue

双重多对多关系

1 个答案: