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Updating items in DynamoDB has two special cases - Conditional Operations and Atomic Counters.  

Conditional Operations and Expressions

By default, the DynamoDB write operations (PutItem, UpdateItem, DeleteItem) are unconditional: each of these operations will overwrite an existing item that has the specified primary key. In certain cases such as multiple users attempting to modify the same item, this might create problems.

Will discuss the basic DynamoDB operations such as create table, and CRUD operations such as insert, read, update and delete.

Creating Table

Can create table using Management Console or CreateTable API.

Insert Data

Can use the PutItem or BatchWriteItem APIs.

PutItem API is idempotent.

DynamoDB primary key fields are called Partition Key and Sort Key. DynamoDB also support two types of secondary indexes, that allows to query on any attribute (column) other that primary key:  Global Secondary Indexes (GSI) and Local Secondary Indexes (LSI).

Data model for DynamoDB comprises of tables, items (rows) and attributes.

Table

A table is a collection of data items.

Table can have a single primary key called partition key or a composite key which contains both partition key and sort key.

Item (row)

An item is synonymous to a row in a traditional database.

1. DynamoDB is integrated with Elasticsearch using the Amazon DynamoDB Logstash Plugin.

   1. With this integration, you can easily search DynamoDB content such as messages, locations, tags, and keywords.

DynamoDB is a fully managed distributed NoSQL database service from Amazon and as per Amazon, it can scale without limits.

 DynamoDB is the most popular NoSQL cloud database according to Forrester, as of Jan 2017.

DynamoDB automatically partitions and re-partitions your data as your table size grows.

An Amazon Machine Image (AMI) provides the information required to launch an EC2 instance.  

You specify an AMI when you launch an instance, and you can launch as many instances from the AMI as you need.

You can also launch instances from as many different AMIs as you need.

An AMI includes the following:

1. A template for the root volume for the instance (for example, an operating system, an application server, and applications)

Amazon home page for DynamoDB:

https://aws.amazon.com/dynamodb/

DynamoDB FAQs:

https://aws.amazon.com/dynamodb/faqs/

Limits in DynamoDB:

http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Limits.html

Reserved Words in DynamoDB:

Amazon DynamoDB Accelerator (DAX) is a fully managed, highly available, in-memory cache for DynamoDB that enables you to benefit from fast in-memory performance for demanding applications. DAX improves the performance of read-intensive DynamoDB workloads so repeat reads of cached data can be served immediately with extremely low latency.

The DynamoDB Storage Backend for Titan is a plug-in that allows you to use DynamoDB as the underlying storage layer for Titan graph database.

It is a client side solution that implements index free adjacency for fast graph traversals on top of DynamoDB.  

Using DynamoDB enables you to run graph workloads without having to manage your own cluster for graph storage.