The Query Tool is the main component through which users construct, refine, and submit i2b2 queries. Query construction is primarily based on drag-and-drop and selecting the appropriate options. This page details the various 'Query Tool' operations and options and how to use 'Query Tool' in conjunction with other components. The Table of Content offers links to quickly jump to relevant topics. In addition, a quick start video show the query process and to demonstrate the basic query-building features.
This video introduces the basic functionalities of the Query Tool through building a series of simple queries.
An i2b2 query is a request that contains users' search criteria for patients stored in an i2b2 database. A query can be sent to an i2b2 server, where it is evaluated and the results are returned to the users after some time. A query typically contains one or more ontology terms users are interested in. For example, users may select ontology terms to query for patients with certain medications, diagnoses, and demographic information. Users can apply constraints to the terms to be more specific about the criteria. When a query is submitted, it will will take some time for i2b2 to process. Query Status will keep track of how long the query takes to run, and show the results when the query completes. When a query completes, the query itself along with all its results are stored in Previous Queries. Some results such as patient sets can also be used in a new query.
Initially the Query Tool shows three Groups to the users, but only one (the first one) is active. Users are to add criteria via drag-and-drop to the Groups to construct their queries. A number of potential i2b2 objects can be added to the Groups. They include ontology terms, previous queries, results of previous queries, and items from the Workplace.
Order of Precedents
(e.g. "Find patients who have a systolic blood pressure reading greater than 130 mm Hg")