Extension:Semantic Compound Queries

MediaWiki extensions manual

Semantic Compound Queries Release status: stable
Implementation	Parser function
Description	Defines a parser function, #compound_query, that can make multiple Semantic MediaWiki queries at the same time
Author(s)	Yaron Koren and others
Maintainer(s)	SMW Project
Latest version	2.1.0 (2019-08-18)
MediaWiki	1.31+
PHP	7.0+
Database changes	No
Composer	mediawiki/semantic-compound-queries
License	GNU General Public License 2.0 or later
Download	GitHub: project page git repository URL [help ] commit history RELEASE NOTES
Example	A Google Map showing two different kinds of points, with a different marker for each
Compatibility Semantic MediaWiki 3.0 and later

The Semantic Compound Queries extension is meant to work with Semantic MediaWiki and allows for the display of more than one SMW inline query in one results display set. It uses its own parser function, #compound_query, which takes inputs similar to that of #ask but can take in an unlimited number of queries, instead of just one.

Installation

The recommended way to install Semantic Compound Queries is by using Composer with an entry in MediaWiki's "composer.local.json" file:

{
    "require": {
        "mediawiki/semantic-compound-queries": "~2.1"
    }
}

Now run the following in the shell:

php composer.phar update --no-dev --prefer-source

To invoke the extension add the following line to the bottom of your "LocalSettings.php" file:

wfLoadExtension( 'SemanticCompoundQueries' );

Usage

A normal inline query, using the #ask parser function, takes in arguments of three types: (1) a filter that determines the results, (2) the names of properties to be displayed, and (3) arguments that determine the format and other aspects of the display. Here is an example of a normal inline query:

{{#ask: [[Category:Stores]] [[Has type::Clothing]] |?Has country=Country |format=table }}

In this query there are three arguments separated by pipes and they belong to argument types 1, 2 and 3, respectively.

For compound queries the first two types of argument are unique to each sub-query and are separated from each other by semicolons instead of pipes; pipes are used to separate one sub-query from the rest. The third type of argument, setting the display of the results, is common across all sub-queries. Here is an example of a call to #compound_query that shows both clothing stores and fast-food restaurants in a table:

{{#compound_query: [[Category:Stores]] [[Has type::Clothing]] ;?Has country=Country
 |[[Category:Restaurants]][[Has cuisine::Fast food]] ;?Has country=Country
 |format=table
}}

One important exception to this rule is the limit= parameter, which sets the maximum number of results displayed: it must be used per sub-query, not for the overall compound query.

Maps

To make things more interesting, we can place all these results on a map, using the Maps extension. Here is the same set of results, using SM's 'googlemaps' format, and a different property displayed for both sets of points to set their geographical coordinates:

{{#compound_query: [[Category:Stores]] [[Has type::Clothing]] ;?Has coordinates
 |[[Category:Restaurants]] [[Has cuisine::Fast food]] ;?Has coordinates
 |format=googlemaps
}}

We can set a different icon to appear for each location type in the map, by using the "icon" parameter, which Semantic Maps understands (note that this feature only works with MediaWiki 1.13 or higher). Assuming your wiki contains uploaded images by the name of "Shirt.png" and "Hamburger.png", you could call the following:

{{#compound_query: [[Category:Stores]] [[Has type::Clothing]] ;?Has coordinates ;icon=Shirt.png
 |[[Category:Restaurants]] [[Has cuisine::Fast food]] ;?Has coordinates ;icon=Hamburger.png
 |format=googlemaps|height=400|width=600
}}

This query also sets the height and width of the map - additional arguments of the third type.

#compound_query avoids displaying the same page more than once, so if a page gets returned by more than sub-query, it's displayed only for the first one. In this way, a compound query can have specific sub-queries, and then a general catch-all sub-query at the end:

{{#compound_query: [[Category:Restaurants]] [[Has cuisine::Fast food]] ;?Has coordinates; icon=Hamburger.png
 |[[Category:Restaurants]][[Has cuisine::Italian]] ;?Has coordinates ;icon=Spaghetti.png
 |[[Category:Restaurants]] ;?Has coordinates ;icon=Fork.png
 |format=googlemaps
}}

Maps displaying the result of a compound query with Google Maps:

Compound query using Google Maps

Compound query using Google Maps

Calendars

There's also special handling for the 'calendar' format, defined in Semantic Result Formats - if you display a calendar, you can set a different color for each set of events displayed. Here is an example:

{{#compound_query: [[Category:Events]] [[Has priority::High]] ;?Has date ;color=red
 |[[Category:Events]] [[Has priority::Low]] ;?Has date ;color=#99cc99
 |[[Category:Events]] ;?Has date
 |format=calendar
}}

API

Starting with version 1.0 this extension provides an API module called "compoundquery". The documentation is available semantic-mediawiki.org

Limitations

• Unlike regular #ask queries, #compound_query does not display a "further results" link if the number of results exceeds the limit. For this reason, the searchlabel parameter available for regular #ask queries cannot be used.

Authors

Semantic Compound Queries was mostly written by Yaron Koren. Important contributions were made by James Hong Kong, Jeroen De Dauw and Peter Grassberger.

Semantic Compound Queries was funded initially by the KDZ - Centre for Public Administration Research in Vienna, Austria.

Version history

Semantic Compound Queries is currently at version 2.1.0. See the entire version history.

Bugs and feature requests

You should use the Semantic MediaWiki mailing list, semediawiki-user, for any questions, suggestions or bug reports about Semantic Compound Queries. If possible, please add "[SCQ]" at the beginning of the subject line, to clarify the subject matter.