Friday, December 23, 2016

DynamoDB Query Filtering

Query Filtering

DynamoDB’s Query function retrieves items using a primary key or an index key from a Local or Global Secondary Index. Each query can use Boolean comparison operators to control which items will be returned.
With today’s release, we are extending this model with support for query filtering on non-key attributes. You can now include a QueryFilter as part of a call to the Query function. The filter is applied after the key-based retrieval and before the results are returned to you. Filtering in this manner can reduce the amount of data returned to your application while also simplifying and streamlining your code.
The QueryFilter that you pass to the Query API must include one or more conditions. Each condition references an attribute name and includes one or more attribute values, along with a comparison operator. In addition to the usual Boolean comparison operators, you can also use CONTAINS, NOT_CONTAINS, and BEGINS_WITH for string matching, BETWEEN for range checking,  and IN to check for membership in a set.
In addition to the QueryFilter, you can also supply a ConditionalOperator. This logical operator (either AND or OR) is used to connect each of the elements in the QueryFilter.

Resource Link:

https://aws.amazon.com/blogs/aws/improved-queries-and-updates-for-dynamodb/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed:+AmazonWebServicesBlog+%28Amazon+Web+Services+Blog%29

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