Working with Local Secondary Indexes in DynamoDB Amazon CLI
You can use the Amazon CLI to create an Amazon DynamoDB table with one or more Local Secondary Indexes, describe the indexes on the table, and perform queries using the indexes.
Topics
Create a table with a Local Secondary Index
Local Secondary Indexes must be created at the same time you create a table. To do
this, use the create-table
parameter and provide your specifications for one or
more Local Secondary Indexes. The following example creates a table (Music
) to hold
information about songs in a music collection. The partition key is Artist
and the sort key is SongTitle
. A secondary index,
AlbumTitleIndex
on the AlbumTitle
attribute facilitates queries by album title.
aws dynamodb create-table \ --table-name Music \ --attribute-definitions AttributeName=Artist,AttributeType=S AttributeName=SongTitle,AttributeType=S \ AttributeName=AlbumTitle,AttributeType=S \ --key-schema AttributeName=Artist,KeyType=HASH AttributeName=SongTitle,KeyType=RANGE \ --provisioned-throughput \ ReadCapacityUnits=10,WriteCapacityUnits=5 \ --local-secondary-indexes \ "[{\"IndexName\": \"AlbumTitleIndex\", \"KeySchema\":[{\"AttributeName\":\"Artist\",\"KeyType\":\"HASH\"}, {\"AttributeName\":\"AlbumTitle\",\"KeyType\":\"RANGE\"}], \"Projection\":{\"ProjectionType\":\"INCLUDE\", \"NonKeyAttributes\":[\"Genre\", \"Year\"]}}]"
You must wait until DynamoDB creates the table and sets the table status to
ACTIVE
. After that, you can begin putting data items into the
table. You can use describe-table
to determine the status of the table creation.
Describe a table with a Local Secondary Index
To get information about local secondary indexes on a table, use the
describe-table
parameter. For each index, you can access its name, key
schema, and projected attributes.
aws dynamodb describe-table --table-name Music
Query a Local Secondary Index
You can use the query
operation on a Local Secondary Index in much the same way that you
query
a table. You must specify the index name, the query criteria for
the index sort key, and the attributes that you want to return. In this example, the
index is AlbumTitleIndex
and the index sort key is AlbumTitle
.
The only attributes returned are those that have been projected into the index. You could modify this query to select non-key attributes too, but this would require table fetch activity that is relatively expensive. For more information about table fetches, see Attribute projections.
aws dynamodb query \ --table-name Music \ --index-name AlbumTitleIndex \ --key-condition-expression "Artist = :v_artist and AlbumTitle = :v_title" \ --expression-attribute-values '{":v_artist":{"S":"Acme Band"},":v_title":{"S":"Songs About Life"} }'