datahub/docs/tutorial-basics-query.markdown

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Dataset Basics - Querying

Preparations

See first Dataset basics tutorial for getting setup and initializing Dataset.

Querying

The basic thing we want to do with Datasets is query and filter them. This is very easy to do:

{% highlight javascript %} {% include tutorial-basics-ex-2.js %} {% endhighlight %}

This results in the following. Note how recordCount is now 3 (the total number of records matched by the query) but that records only contains 2 records as we restricted number of returned records using the size attribute.

 

Full details of the query structure and its options can be found in the reference documentation.

Also worth noting is that the last run query is stored as a Query instance in the queryState attribute of the Dataset object. Modifying queryState will also resulting in a query being run. This is useful when building views that want to display or manage the query state (see, for example, Query Editor or Filter Editor widgets).