dynamodb query sort descending

In the previous post I insertd a few rows in a Demo table using the SQL-like new API on DynamoDB. If the table or index has a sort key, you can refine the results by providing a sort key value and a condition. The results always return in sort key order, and data type based order with the modifiable default as the ascending order. You must provide a partition key value and an equality condition. When we query for GSI1PK = “User-1/Folder-1/” and sort the results by GSI1SK in descending key order, the first result is Folder-1 (because ~ comes after all other keys) and the following results are File-2 and File-3 in descending date order. Search Forum : Advanced search options This thread is locked - replies are not allowed. The Sort Key is primarily used to narrow down results for items with a particular hash key. Once you select the query option. You can query any table or secondary index that has a composite primary key (a partition key and a sort key). Using the SELECT statement can result in a full table scan if an equality condition with a partition key is not provided in the WHERE clause. When using a Sort key, records on the partition are logically grouped together in Ascending order. By Franck Pachot . Description¶. The Query operation enables you to query a table or a secondary index in Amazon DynamoDB. You cannot query using category only. DynamoDB has two capacity modes, ... aws dynamodb query finds items based on primary key values. For more information, see ConditionalOperator in the Amazon DynamoDB Developer Guide. By specifying a Sort Key, the table’s Primary Key becomes a composite of the Partition Key and Sort Key. level 2. You can query using either Author or using Author and Category both. Query by Partition Key Sort Key. The query processes by performing retrievals in sort key order, and using any condition and filter expressions present. Use the SELECT statement to retrieve data from a table in Amazon DynamoDB.. ScanIndexForward: Specifies the order for index traversal: If true (default), the traversal is performed in ascending order; if false, the traversal is performed in descending order. Use the KeyConditionExpression parameter to provide a specific value for the partition key. The Sort Key isn’t used in the above query, as specifying a Sort Key is optional in a query statement. As the category is the sort key. Discussion Forums > Category: Database > Forum: Amazon DynamoDB > Thread: Query Data using multiple partition keys and sort key descending. Here is the most important to understand: there are no additional data processing engine here. The query operation always returns a result set in the items key, which can be empty if no record is found matching the criteria specified by the query. I just put out a video on Querying DynamoDB from Lambda. The Query operation finds items based on primary key values. The Query operation will return all of the items from the table or index with that partition key value. To get them sorted, you need to use a sort key. ... (use ScanIndexForward to False to reverse order to descending) Capacity Modes. For more on interacting with items, start with the lesson on the anatomy of an item . The query should at least contain the partition key which in our case in the Author. The composite primary key enables sophisticated query patterns, including grabbing all items with the given partition key or using the sort key to narrow the relevant items for a particular query. Items with the same partition key value are stored in sorted order by sort key. I'm using Date as a sort … Note that this increases how many writes you get charged for. A scan operation examines every item for the requested values and can use up the provisioned throughput for a large table or index in a single operation. You will have an option to specify what query you want to perform. 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