View source for User:Alexander.Gesinn/WD 2021-03-22

== Initial Situation ==
A table defined by
<source lang="text">
{{#ask:[[IsA::Event]]
 |?Acronym
 |mainlabel=Event
 | ?End_date = end_date
 | ?Start_date = start_date
 | limit=20
 |format=table
}}
</source>

== Task 1: Increase the limit ==
Increase the limit to the maximum value that is possible according to the current configuration of OpenResearch.

The above query is using the parameter <code>limit</code> to restrict the maximum number of results that are returned. By removing <code>limit</code>, the number of results is limited by configuration parameter <code>[https://www.semantic-mediawiki.org/wiki/Help:$smwgQMaxInlineLimit $smwgQMaxInlineLimit]</code> (default: 500). The number of results returned before the "...further results" link is shown can be configured by <code>[https://www.semantic-mediawiki.org/wiki/Help:$smwgQDefaultLimit $smwgQDefaultLimit]</code> (default: 50).

;Solution
<source lang="text">
{{#ask:[[IsA::Event]]
  |?Acronym
  |?End_date=end_date
  |?Start_date=start_date
  |format=table
}}
</source>

{{#ask:[[IsA::Event]]
  |?Acronym
  |?End_date=end_date
  |?Start_date=start_date
  |format=table
}}

== Task 2: Modify query to use datatables ==
The [https://www.semantic-mediawiki.org/wiki/Help:Datatables_format datatables format] is used to enable the data in the table to be searched.

<source lang="text">
{{#ask:[[IsA::Event]]
  |?Acronym
  |?End_date=end_date
  |?Start_date=start_date
  |mainlabel=Event
  |format=datatables
}}
</source>

{{#ask:[[IsA::Event]]
  |?Acronym
  |?End_date=end_date
  |?Start_date=start_date
  |mainlabel=Event
  |format=datatables
}}

== Task 3: Add additional field/column ==
Add an additional frequently used field/column to be selected from the properties listed on the [[PropertyUsageSorted]] page, e.g., Ordinal.

<source lang="text">
{{#ask:[[IsA::Event]]
  |?Acronym
  |?End_date=end_date
  |?Start_date=start_date
  |?Ordinal
  |mainlabel=Event
  |format=datatable
}}
</source>

{{#ask:[[IsA::Event]]
  |?Acronym
  |?End_date=end_date
  |?Start_date=start_date
  |?Ordinal
  |mainlabel=Event
  |format=datatable
}}

== Task 4: UrlGetParameter ==
* The [https://www.mediawiki.org/wiki/Extension:UrlGetParameters UrlGetParameter extension is used so that a query parameter can be attached to the page URL], e.g., the ordinal value "1" is specified as an URL query parameter, such that the wiki pages shows a table only with entries for conferences that were the first in their series.
* [https://github.com/SmartDataAnalytics/OpenResearch/issues/16 Issue #16] is avoided.

;Solution
* Note 1: Parameters passed via URL should be encoded using only the limited US-ASCII characters legal within a URI. This is done automatically by Extension:UrlGetParameters, e.g. <code>test=A:B</code> will be returned as <code>test=A%3AB</code> by <code>#urlget</code>. Thus decoding might be required before using parameters.
* Note 2: If a parameter is optional, code that relies on that parameter, needs to deal with absence of the parameter without causing issues.
* Note 3: If a parameter is expected to be a specific data type / format, code that relies on that data type / format, needs to implement checks ("never trust a stranger unless he gives you candy"). https://www.mediawiki.org/wiki/Extension:RegexFunctions can help with that.
* Note 4: If a parameter is expected to allow multiple values, further processing needs to be done to transform the values to an ask query compliant format (e.g. using Page Forms <code>#arraymap</code> parser function or functionality provided by https://www.mediawiki.org/wiki/Extension:Arrays or https://www.mediawiki.org/wiki/Extension:Variables.

{{#if:{{#urlget:ordinal}}|Showing results for <code>Ordinal={{#urldecode:{{#urlget:ordinal}}}}</code>:|No <code>Ordinal</code> given, showing all results:}}

{{#ask:[[IsA::Event]]{{#if:{{#urlget:ordinal}}|[[Ordinal::{{#urldecode:{{#urlget:ordinal}}}}]]}}
  |?Acronym
  |?End_date=end_date
  |?Start_date=start_date
  |?Ordinal
  |mainlabel=Event
  |format=datatable
}}