AppSync with DynamoDB (GraphQL) - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is AWS AppSync?

AWS AppSync is a service that makes it easy to build GraphQL APIs by handling the heavy lifting of securely connecting to data sources like DynamoDB, Lambda, and more.

beginner

How does AppSync connect to DynamoDB?

AppSync connects to DynamoDB using resolvers that translate GraphQL requests into DynamoDB operations like GetItem, PutItem, Query, and Scan.

beginner

What is a resolver in AppSync?

A resolver is a piece of code or configuration that tells AppSync how to fetch or modify data from a data source when a GraphQL query or mutation is executed.

intermediate

Why use GraphQL with DynamoDB via AppSync instead of direct DynamoDB calls?

GraphQL with AppSync provides a flexible API that lets clients request exactly the data they need, reduces over-fetching, and simplifies real-time updates and offline support.

intermediate

What is a common pattern for modeling data in DynamoDB for AppSync?

A common pattern is to use a single table design with partition keys and sort keys to efficiently query related data, enabling fast and flexible access through GraphQL queries.

What does a resolver in AppSync do?

A Translates GraphQL requests to data source operations

B Stores data in DynamoDB

C Creates GraphQL schemas

D Manages user authentication

Resolvers translate GraphQL queries or mutations into operations on data sources like DynamoDB.

Which AWS service is used to build GraphQL APIs that connect to DynamoDB?

A AWS Lambda

B Amazon S3

C Amazon RDS

D AWS AppSync

AWS AppSync is the service designed to build GraphQL APIs and connect them to data sources like DynamoDB.

In AppSync, what type of DynamoDB operation would a 'Query' resolver perform?

A Retrieve multiple items based on partition key and optional sort key

B Delete a single item

C Add a new item

D Scan the entire table

A Query operation retrieves items matching a partition key and optionally a sort key, which is efficient for related data.

What is a benefit of using GraphQL with AppSync over REST APIs for DynamoDB?

A GraphQL does not support mutations

B Clients can request only the data they need

C AppSync automatically creates tables

D GraphQL requires no schema

GraphQL lets clients specify exactly which fields they want, reducing over-fetching compared to REST.

Which of these is NOT a typical data source for AppSync?

A DynamoDB

B Amazon S3

C Amazon EC2

D AWS Lambda

Amazon EC2 is a compute service, not a typical direct data source for AppSync.

Explain how AWS AppSync works with DynamoDB to serve GraphQL requests.

Think about the flow from client to database and back.

Describe the advantages of using GraphQL with AppSync over direct DynamoDB API calls.

Consider client experience and API flexibility.