type Event {    id: ID!    name: String    where: String    when: String    description: String    # Paginate through all comments belonging to an individual post.    comments(limit: Int, nextToken: String): CommentConnection}

 AWS AppSync 是API的一种新标准；Schema是它的核心，SDL是Schema的主要语言。

 

schema {    query: Query    mutation: Mutation    subscription: Subscription}

 

 

 

1. query 查询语句：

type Query {    # Get a single event by id.    getEvent(id: ID!): Event    # Paginate through events.    listEvents(filter: TableEventFilterInput, limit: Int, nextToken: String): EventConnection}

例子：

query{  getEvent(id: "c16701cb-d614-4f21-b733-a636bc1c8437" ){    description    name  }}

 

返回 json:

{  "data": {    "getEvent": {      "description": "test",      "name": "landen"    }  }}

　　2. mutation 

type Mutation {    # Create a single event.    createEvent(        name: String!,        when: String!,        where: String!,        description: String!    ): Event    # Delete a single event by id.    deleteEvent(id: ID!): Event    # Comment on an event.    commentOnEvent(eventId: ID!, content: String!, createdAt: String!): Comment}

 

• • createEvent 添加事件　　  

　　　　　　　　

mutation{  createEvent(    name: "landen",    when: "2018-08-18",    where: "guangdong",    description: "today is rainny"  ){    id    name  }}

返回 json:

{  "data": {    "getEvent": {      "description": "test",      "name": "landen"    }  }}

• • 　commentOnEvent 更改事件： 　　

mutation{  commentOnEvent(    eventId: "c16701cb-d614-4f21-b733-a636bc1c8437",    content: "comment : rainny",    createdAt: "today"  ){    eventId  }}

返回 json:

{  "data": {    "commentOnEvent": {      "eventId": "c16701cb-d614-4f21-b733-a636bc1c8437"    }  }}

 

• • deleteEvent 删除事件：

mutation{  deleteEvent(id: "c16701cb-d614-4f21-b733-a636bc1c8437"){    name     description  }}

返回 json:

{  "data": {    "deleteEvent": {      "name": "landen",      "description": "test"    }  }}

 

　　3.  subscription 订阅事件：

type Subscription {    subscribeToEventComments(eventId: String!): Comment        @aws_subscribe(mutations: ["commentOnEvent"])}

subscription{  subscribeToEventComments(eventId:"b5a25e27-8416-4486-8df1-27c185520074"){    content    @aws_subscribe(  mutations:["commentOnEvent"])  }  }