diff --git a/README.md b/README.md index 97ddd87..7edceba 100644 --- a/README.md +++ b/README.md @@ -1020,6 +1020,7 @@ DynamoDB - There is a [local version](https://aws.amazon.com/blogs/aws/dynamodb-local-for-desktop-development/) of DynamoDB provided for developer use. - [DynamoDB Streams](http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Streams.html) provides an ordered stream of changes to a table. Use it to replicate, back up, or drive events off of data - DynamoDB can be used [as a simple locking service](https://gist.github.com/ryandotsmith/c95fd21fab91b0823328). +- DynamoDB indexing can include **primary** **keys**, which can either be a single-attribute hash key or a composite hash-key range. You can also query non-primary key attributes using [**secondary** **indexes**](https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/SecondaryIndexes.html). ### DynamoDB Gotchas and Limitations @@ -1027,7 +1028,7 @@ DynamoDB - It is important to make sure that DynamoDB [resource limits](http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Limits.html#limits-data-types) are compatible with your dataset and workload. For example, the maximum size value that can be added to a DynamoDB table is 400 KB (larger items can be stored in S3 and a URL stored in DynamoDB). - 🔸 Dealing with **time series data** in DynamoDB can be challenging. A global secondary index together with down sampling timestamps can be a possible solution as explained [here](https://blogs.aws.amazon.com/bigdata/post/Tx3KPZDXIBJEQ4B/Scaling-Writes-on-Amazon-DynamoDB-Tables-with-Global-Secondary-Indexes). - DynamoDB does [not allow](https://forums.aws.amazon.com/thread.jspa?threadID=90137) an empty string as a valid attribute value. The most common work-around is to use a substitute value instead of leaving the field empty. - +- Data Types: DynamoDB supports three [data types](http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/DynamoDBMapper.DataTypes.html) -- **number**, **string**, and **binary** -- in both scalar and multi-valued sets. DynamoDB can also support [JSON](https://aws.amazon.com/blogs/aws/dynamodb-update-json-and-more/). ECS ---