如何在 graphql 突变中设置多对多关系？

Question

我可能遗漏了一些东西，但在 Apollo 文档中找不到任何关于在创建新条目时设置多对多关系的信息。

当关系是一对多时，只需在多方对象中设置关系一方的 ID 即可。

但让我们假装我正在使用书籍和作者，我将如何编写一个 graphql 查询来为一个（或多个？）作者创建一本书？

Answer 1

这应该可能发生在 GraphQL 服务器的 API 层（即模式）。对于多对多关系，您应该有一个 "join" 类型来表示 BookAuthor 多对多关系，然后向该连接类型添加一个条目。

基本上，您将拥有一个名为 Book 的类型，另一个名为 Author，最后还有一个名为 BookAuthor。你可以添加一些突变来管理这种关系。也许...

addToBookAuthorConnection
updateBookAuthorConnection
removeFromBookAuthorConnection

这是使用符合中继规范的常规设置 API。你可以 read more about how to structure your API for many-to-many relationships here.

然后，您只需要从 Apollo 调用 addToBookAuthorConnection 突变，就可以添加到前端的多对多连接。

希望对您有所帮助！

Answer 2

如果您使用具有一对多关系的 apollo 图服务器，则 connectors.js、resolvers.js 和 schema.js 文件为给定格式

schema.js

const typeDefinitions = `



type Author {

  authorId: Int
  firstName: String
  lastName: String
  posts: [Post]

}

type Post {

  postId: Int
  title: String 
  text: String
  views: Int
  author: Author

}

input postInput{
  title: String 
  text: String
  views: Int
}


type Query {

  author(firstName: String, lastName: String): [Author]
  posts(postId: Int, title: String, text: String, views: Int): [Post]

}



type Mutation {

createAuthor(firstName: String, lastName: String, posts:[postInput]): Author

updateAuthor(authorId: Int, firstName: String, lastName: String, posts:[postInput]): String

}


schema {
  query: Query
  mutation:Mutation
}
`;

export default [typeDefinitions];

resolvers.js

import { Author } from './connectors';
import { Post } from './connectors';


const resolvers = {

  Query: {
    author(_, args) {
      return Author.findAll({ where: args });
    },
    posts(_, args) {
      return Post.findAll({ where: args });
    }
  },

  Mutation: {

    createAuthor(_, args) {
      console.log(args)
      return Author.create(args, {
        include: [{
          model: Post,
        }]
      });
    },

    updateAuthor(_, args) {

      var updateProfile = { title: "name here" };
      console.log(args.authorId)
      var filter = {
        where: {
          authorId: args.authorId
        },
        include: [
          { model: Post }
        ]
      };
      Author.findOne(filter).then(function (product) {
        Author.update(args, { where: { authorId: args.authorId } }).then(function (result) {
          product.posts[0].updateAttributes(args.posts[0]).then(function (result) {
            //return result;
          })
        });
      })
      return "updated";
    },

  },


  Author: {
    posts(author) {
      return author.getPosts();
    },
  },
  Post: {
    author(post) {
      return post.getAuthor();
    },
  },
};

export default resolvers;

connectors.js

import rp from 'request-promise';
var Sequelize = require('sequelize');
var db = new Sequelize('test', 'postgres', 'postgres', {
  host: '192.168.1.168',
  dialect: 'postgres',

  pool: {
    max: 5,
    min: 0,
    idle: 10000
  }

});


const AuthorModel = db.define('author', {
  authorId: { type: Sequelize.INTEGER, primaryKey: true, autoIncrement: true, field: "author_id" },
  firstName: { type: Sequelize.STRING, field: "first_name" },
  lastName: { type: Sequelize.STRING, field: "last_name" },
},{
        freezeTableName: false,
        timestamps: false,
        underscored: false,
        tableName: "author"
    });


const PostModel = db.define('post', {
    postId: { type: Sequelize.INTEGER, primaryKey: true, autoIncrement: true, field: "post_id" },
  text: { type: Sequelize.STRING },
  title:  { type: Sequelize.STRING },
  views: { type: Sequelize.INTEGER },
},{
        freezeTableName: false,
        timestamps: false,
        underscored: false,
        tableName: "post"
    });


AuthorModel.hasMany(PostModel, {
    foreignKey: 'author_id'
});
PostModel.belongsTo(AuthorModel, {
    foreignKey: 'author_id'
});

const Author = db.models.author;
const Post = db.models.post;

export { Author, Post };

如何在 graphql 突变中设置多对多关系？

how to set many-to-many relation in graphql mutation?

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graphql

react-apollo