Extension:Semantic OLAP

Semantic OLAP is an extension to Semantic MediaWiki that allows to query and analyse data, stored in the semantic MediaWiki, by using OLAP functionality. Users can analyse the data from different views by changing the pivot table. Semantic OLAP uses orbjs, which is based on React.js, to customize and control the pivot table.

Installation

 * Semantic MediaWiki must be installed in order to use Semantic OLAP.

Select Data
In the initial screen of the Semantic OLAP Special Page, the data that should be queried must be selected.
 * At least one Category and one Property must be selected.
 * Autocomplete simplifies the input and suggests available Categories and Properties

On the basis of the input, a simple ASK Query is created in the background. If no result is returned, a Popup appears with the corresponding ASK query.



Analyse Data
Tool allows to analyse the data by using OLAP functionality.
 * Use Drag&Drop to change the view on the pivot table
 * Hashtags (#) in front of a property represents the amount of assigned values to this property. The Hashtag property does only appear if multiple values were assigned to the property.
 * If a property is of type "Quantity", the corresponding unit is displayed. Please have a look at Known Issues if the unit is not displayed
 * Click on "Select Data" to get back to the initial screen and select the data for analysis



Filter and Sort Values
Semantic OLAP allows to filter for values. In order to filter, click on the right icon on the corresponding property and filter vor values either by
 * Matches (i.e. greater than, lower than)
 * Tick the concrete values



Export Data
The current view on the data is downloaded in spreadsheet format by clicking on the export xls button.



Future Work

 * Select aggregation function (sum, avg, max, min)
 * Currently, only sum is available
 * Advanced ASK Queries/Selection of data
 * Using advanced queries in SMW 2.5
 * Compound Queries
 * Allow to display information in graphs

Remarks

 * Not all units are displayed. It is part of future work to display all available units
 * Sometimes the Multibox is not properly loaded. Please reload the page in that case