Extension:Semantic Compound Queries

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Semantic Compound Queries Release status: beta
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 <yaron57@gmail.com>
Last Version	0.2.3 (October 2009)
MediaWiki	1.11.* or greater
License	GPL
Download	See here
Example	A map showing both people and organizations, with a different icon for each A calendar of opinion items before the 2008 U.S. presidential election, color-coded by candidate
check usage (experimental)

[edit] Description

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

This extension requires version 1.2 or greater of Semantic MediaWiki.

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

[edit] Download

You can download the Semantic Compound Queries code in either one of these two compressed files:

• semantic_compound_queries_0.2.3.tar.gz
• semantic_compound_queries_0.2.3.zip

You can also download the code directly via SVN from the MediaWiki source code repository, at http://svn.wikimedia.org/svnroot/mediawiki/trunk/extensions/SemanticCompoundQueries/. From a command line, you can call the following:

svn checkout http://svn.wikimedia.org/svnroot/mediawiki/trunk/extensions/SemanticCompoundQueries/

You can also view the code here.

[edit] Installation

To install this extension, create a 'SemanticCompoundQueries' directory (either by extracting a compressed file or downloading via SVN), and place this directory within the main MediaWiki 'extensions' directory. Then, in the file 'LocalSettings.php', somewhere below the inclusion of Semantic MediaWiki (both the main 'include_once' line and the 'enableSemantics' line), add the following line:

include_once("$IP/extensions/SemanticCompoundQueries/SemanticCompoundQueries.php");

(Note that, until version 0.2.3, this file was called "SCQ_Settings.php" - if you're upgrading from a previous version of Semantic Compound Queries, you'll need to change the call.)

[edit] Author

Semantic Compound Queries was written by Yaron Koren, reachable at yaron57 -at- gmail.com.

[edit] Version

Semantic Compound Queries is currently at version 0.2.3.

The version history is:

• 0.1 - November 19, 2008 - Initial version
• 0.2 - November 25, 2008 - Two defined classes moved to their own files; fix for semicolons contained within query filters
• 0.2.1 - December 1, 2008 - Fix for map icons with MW 1.12 or earlier
• 0.2.2 - June 4, 2009 - Added internationalization, for extension description
• 0.2.3 - October 13, 2009 - Added support for SMW 1.5, removed support for MW 1.11 and earlier

[edit] 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}}

To make things more interesting, we can place all these results on a map, using the Semantic 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}}

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}}

[edit] 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.

You can also send specific code patches to Yaron Koren, at yaron57 -at- gmail.com.