graphql(三)——graphql+node+express+mongodb实现增删改查

接着上节学习graphql+node+express+mongodb实现增删改查及两表关联。

先定义schema

以集合user为例子：

• graphql中定义schema(schema.js)

  type User{
       name:String,
       age:Int,
       id:String,
       status:String,
       msg:String
   }
   
   type Query {
       getUser:[User]
   }
  
   type Mutation{
       createUser(argsMutify:MutifyUser):User
       updateUser(argsMutify:MutifyUser):User
       deleteUser(id:String):User
   }
  
  input MutifyUser{
      name:String,
      age:Int,
      status:String,
      msg:String,
      id:String
  }
  

• 数据库中(models/user.js)

  var mongoose = require('mongoose');
  var Schema = mongoose.Schema;
  
  var userSchema = new Schema({
    name: String,
    age: Number
  });
  
  module.exports = mongoose.model("user", userSchema)
  

resolver

• 查

  getUser() {
  	return User.find();   //User是在resolver文件中引入的集合
  }
  

• 增

  async createUser(root, {
     argsMutify
  }) {
      let newData = {};
      await User.findOne({   //在User集合中查找增加的数据是否存在
          "name": argsMutify.name
      }).then(async (dataUser) => {
          if (!dataUser) {
              await User.insertMany(argsMutify)
                  .then((data) => {
                      newData = data[0];
                  });
              newData.status = 200;
              newData.msg = "增加成功！"
          } else {
              newData.status = 403;
              newData.msg = "增加失败，数据已存在！"
          }
      });
      return newData;
  }
  

• 改

  async updateUser(root, {
     argsMutify
  }) {
      let newData;
      await User.findByIdAndUpdate({
          _id: argsMutify.id
      }, {
          $set: {
              name: argsMutify.name,
              age: argsMutify.age
          }
      }, {
          new: true      //加上此句返回的数据是修改之后的，否则返回的是修改之前的
      }).then((data) => {
          if (data) {
              newData = data;
              newData.status = 200;
              newData.msg = "编辑成功！"
          } else {
              newData.status = 403;
              newData.msg = "编辑失败！"
          }
  
      })
      return newData
  }
  

• 删

  async deleteUser(root, {
     id
  }) {
      let newData = {};
       await User.deleteOne({
          "_id": id
      }).then((data) => {
          newData.status = 200;
          newData.msg = "删除成功！"
      })
      return newData
  }
  

表关联

以两个表(user和post)之间的关联为例子(user集合中的id与post集合中的author关联)，所以在上面的schema中加入定义集合post的内容。两表关联用populate与aggregate 2种方法，但是后者关联时拿不到数据，所以采用前者关联表，在使用之前先得了解populate的语法,若会用populate的可以直接进入下面步骤：

• graphql中定义schema

  type Post{
      title: String,
      content: String,
      id:String,
      author:User,
      msg:String,
      status:String
  }
  
  type Query {
     getPost(author:String):Post
  }
  
  type Mutation{
     createPost(argsMutify:MutifyPost):Post
  }
  
  input MutifyPost{
      title: String,
      content: String,
      author:String,
      msg:String,
      status:String
  }
  

• 数据库中model

  • user集合中的model与schema

    var mongoose = require('mongoose');
    var Schema = mongoose.Schema;
    
    var userSchema = new Schema({
      name: String,
      age: Number
    });
    
    module.exports = mongoose.model("user", userSchema)
    
    

  • post集合中的model与schema

    var mongoose = require('mongoose');
    var Schema = mongoose.Schema;
    
    var postSchema = new Schema({
        title: String,
        content: String,
        author: {type: Schema.Types.ObjectId, ref: 'user'}  // ref选项可以告诉Mongoose在填充过程中使用哪种模型，在示例中是User模型。在此处存储的所有_id必须是User模型中的文档_id。
      });
      
    module.exports = mongoose.model("post", postSchema)
    

• resolver
  • 查

    async getPost(root, agrs, context) {
        let message;
        await Post.findOne({
                "author": agrs.author
            })
            .populate('author', 'name age').exec()
            .then((post) => {
                message = post;
            });
        return message;
    }
    

  • 增

    async createPost(root, {
         argsMutify
     }) {
         let newData={};
        await Post.findOne({
             "author":argsMutify.author
         }).then(async(data)=>{
             if(!data){
                await Post.insertMany(argsMutify).then((dataPost) => {
                     newData=dataPost[0];
                 })
                 newData.status=200;
                 newData.msg="增加成功！"
             }else{
                 newData.status=403;
                 newData.msg="增加失败，数据已存在！"
             }
         })
         return newData;
     }
    

graphql结合apollo-serve(中间件)、express(快速搭建服务)、mongoDB(数据库)实现增删改查及表关联已已经完成啦 ✌️ ✌️✌️，因为是初次接触，若有问题欢迎在下面指正！

相关链接

• populate
• aggregate