dabit3

type User @model
@key(name: "byUserIdIndex", fields: ["userId"], queryField: "userById")
@auth(
  rules: [
    { allow: owner, ownerField: "userId" }
  ]) {
  id: ID!
  userId: ID!
  type: String!
  events: [EventLink] @connection(keyName: "EventUserIndex", fields: ["userId"])

dabit3

type Base @model("BaseDB") {
  id: ID!
}

type Post @db("BaseDB") {
  ...Base
  name: String!
}

type Comment @db("BaseDB") {

dabit3

type Product @model
  @key(name: "productSortedIndex", fields: ["baseType", "createdAt"], queryField: "productsSorted") {
  id: ID
  name: String
  price: Float
  createdAt: String
  baseType: String
}

dabit3

{
    "version": "2018-05-29",
    "operation": "UpdateItem",
    "key" : {
      "id" : $util.dynamodb.toDynamoDBJson($context.arguments.id)
    },
    "update": {
      "expression" : "set #upvotes = #upvotes + :updateValue",
      "expressionNames" : {
           "#upvotes" : "upvotes"

dabit3

type Product @model
  @key(name: "productInventoryAmountIndex", fields: ["baseType", "inventory"], queryField: "productsByInventoryAmount")
  @key(name: "productInventoryPriceIndex", fields: ["baseType", "price"], queryField: "productsByPrice")
  @key(name: "productNameSearchIndex", fields: ["baseType", "name"], queryField: "productSearchByName")
  @key(name: "productCategorySearchIndex", fields: ["baseType", "category"], queryField: "productSearchByCategory")
  @key(name: "productCategoryIndex", fields: ["category", "createdAt"], queryField: "productsByCategory")
  @key(name: "productByCategoryAndNameIndex", fields: ["category", "name"], queryField: "productsByCategoryAndName")
  @key(name: "productByCategoryAndInventoryIndex", fields: ["category", "inventory"], queryField: "productsByCategoryAndInventory")
  @key(name: "productByCategoryAndPriceIndex", fields: ["category", "price"], queryField: "productsByCategoryAndPrice")
{

dabit3

/* This file contains two files */

/* index.py */
import json

def handler(event, context):
  body = {
    "message": "Hello from Lambda!"
  }

dabit3

import Amplify from '@aws-amplify/core'
import config from './aws-exports'
Amplify.configure(config)

import React, { useState, useEffect } from 'react'
import { Text, View, TextInput, Button } from 'react-native'
import { DataStore } from '@aws-amplify/datastore'
import { Message} from './src/models'

const initialState = { color: 'black', title: '' }

dabit3

import React, { useState, useEffect } from 'react'
import { SketchPicker } from 'react-color'
import { Input, Button } from 'antd'
import { DataStore } from '@aws-amplify/datastore'
import { Message} from './models'

const initialState = { color: '#000000', title: '', }

function App() {
  const [formState, updateFormState] = useState(initialState)

dabit3

type Post @model
  @auth(rules: [
    # Owner can create, update, delete
    { allow: owner },
    # Authorize group-based access control
    { allow: groups, groups: ["Admin"] }
  ]) {
  id: ID!
  title: String!
  content: String

dabit3

Building offline apps with Amplify DataStore

To view and deploy the app covered in this chapter, check out this repo.

So far in this book we've worked with both REST APIs and GraphQL APIs. When working with the GraphQL APIs so far, we've used the API class to directly call mutations and queries against the API.

Amplify also supports another type of API for interacting with AppSync, Amplify DataStore. DataStore has a different approach than a traditional GraphQL API.

Instead of interacting with the GraphQL API itself using queries and mutations, DataStore introduces a client-side SDK that persists the data locally using the local storage engine of the platform you are working with (i.e. IndexDB for web, SQLLite for native iOS and Android). DataStore then automatically syncs the local data to the GraphQL backend for you as updates are made both locally and remotely.