Relay/GraphQL'如何解决'有效吗？

Question

我正在尝试Relay和GraphQL.当我在做模式时,我这样做:

let articleQLO = new GraphQLObjectType({
  name: 'Article',
  description: 'An article',
  fields: () => ({
    _id: globalIdField('Article'),
    title: {
      type: GraphQLString,
      description: 'The title of the article',
      resolve: (article) => article.getTitle(),
    },
    author: {
      type: userConnection,
      description: 'The author of the article',
      resolve: (article) => article.getAuthor(),
    },
  }),
  interfaces: [nodeInterface],
})

所以,当我要求这样的文章时:

{
  article(id: 1) {
    id,
    title,
    author
  }
}

它会对数据库进行3次查询吗？我的意思是,每个字段都有一个解析方法(getTitle,getAuthor ...),它向数据库发出请求.我做错了吗？

这是getAuthor的一个例子(我使用mongoose):

articleSchema.methods.getAuthor = function(id){
  let article = this.model('Article').findOne({_id: id})
  return article.author
}

Answer 1

如果该resolve方法传递给article，您不能只访问该属性吗？

let articleQLO = new GraphQLObjectType({
  name: 'Article',
  description: 'An article',
  fields: () => ({
    _id: globalIdField('Article'),
    title: {
      type: GraphQLString,
      description: 'The title of the article',
      resolve: (article) => article.title,
    },
    author: {
      type: userConnection,
      description: 'The author of the article',
      resolve: (article) => article.author,
    },
  }),
  interfaces: [nodeInterface],
})

由于Schema.methodsMongoose 在model 上定义了方法，因此它不需要文章的 ID（因为您在文章实例上调用它）。因此，如果您想保留该方法，只需执行以下操作：

articleSchema.methods.getAuthor = function() {
  return article.author;
}

如果您需要在另一个集合中查找它，那么您需要执行单独的查询（假设您不使用引用）：

articleSchema.methods.getAuthor = function(callback) {
  return this.model('Author').find({ _id: this.author_id }, cb);
}