mongoDb + graphQL

1. create folder server, cd server
2. type npm init -y
3. type npm install graphql-yoga
4. create index.js in server
5. install mongoDB, start mongod.exe
6  type npm install mongoose
7. type node index.js
8. web browser go to localhost:4000

display

left graphQL, right mongo compass

{

  profiles{

    id,

    name,

    amount,

    category,

    date

  }

}

---------------------------------------------------------------------------

create

create new profile sam

mutation{
  createProfile(name: "sam", category: 1,
  amount: 50.3){
    id,
    name,
    amount,
    date,
    category
  }
}
--------------------------------------------------------------------------

update

update amount of sam to 88888

mutation{

  updateProfile(

    id:"5b3d9ac7e2cf8334843741f2",

   amount:888888

  )

}

----------------------------------------------------------------------

delete

sam is removed

mutation{

  removeProfile(id:"5b3d9ac7e2cf8334843741f2")

}

--------------------------------------------------------------------------

//index.js

const { GraphQLServer } = require('graphql-yoga');
const mongoose = require('mongoose');

mongoose.connect('mongodb://localhost/db1');

const transactionSchema = mongoose.Schema({
    name: String,
    amount: Number,
    category: Number,
    date: String,
});
const transactionModel = mongoose.model('transactionModel', transactionSchema);

const typeDefs = `
  type Query {
    hello(name: String): String!
    profiles: [transactionModel]
  }
 type transactionModel{
  id: ID!
  name: String!
  amount: Float!
  category: Int
  date: String
}
 type Mutation{
   createProfile(name: String!, amount: Float, category: Int): transactionModel
   updateProfile(id:ID!, name: String!, category: Int, amount: Float) : Boolean
   removeProfile(id:ID!): Boolean
}
`

const resolvers = {
    Query: {
        hello: (_, { name }) => `Hello ${name || 'World'}`,
        profiles: ()=> transactionModel.find()
    },
    Mutation: {
        createProfile: async (_, { name, amount, category }) => {
            const transctionTime = new Date();

            const profile = new transactionModel({
                name: name,
                amount: amount || 0,
                category: category || 0,
                date: transctionTime.toLocaleString(),
            });

            await profile.save();
            return profile;
        },
        updateProfile: async (_, { id, name, category, amount }) => {
            const transctionTime = new Date();

            await transactionModel.findByIdAndUpdate(id,
                {
                    name: name,
                    amount: amount,
                    category: category,
                });
            return true;
        },
        removeProfile: async (_, { id }) => {
            await transactionModel.findByIdAndRemove(id);
            return true;
        }
    }
}

const server = new GraphQLServer({ typeDefs, resolvers });
const db = mongoose.connection;
db.on('error', console.error.bind(console, 'connection error:'));
db.once('open', function () {
    // we're connected!
    server.start(() => console.log('Server is running on localhost:4000'))
});

reference:
http://chuanshuoge2.blogspot.com/2018/06/react-mongodb.html