Related schema

A query is always performed among the properties/values of a given schema, simply using the following parameter:

|schema=[my schema]

Conditions

The query is the first argument of the parser function visualdataquery and looks as follows:

[[name::Afghanistan]] [[states/name::Badakhshan]]

Each string surrounded by double square brackets represents a query condition, where the string before the double colon represents the property path (called "printout" in the dialect of Visual Data), and the string on the right is the value to be matched.

The following search operators are currently supported:

This allows to safely perform standard SQL queries on your set of data. For instance the following condition

[[name::Afghanistan]] [[states/cities/name::B~]]

matches all json data (in our case with schema "contry") with property "name" with value "Afghanistan" and (within such schema) all cities with name starting with "B".

The following matches all cities with a population of more than 3000000 units. Note that the property name is always preceded by two double colons, also with comparison operators, in order to distinguish it by titles or special properties (like Creation date and Modification date).

[[city::+]][[population:: > 3000000]]

Specific pages or categories can be inserted in the query in the following way:

[[My Article]][[Category:Category a||Category:Category b]]

where the query will search for a page with title "My article" with category "Category a" or "Category b". In order to search a page with title "My article" with category "Category a" and "Category b" use:

[[My Article]][[Category:Category a]][[Category:Category b]]

A query can also contain just the article id or pagetitle (without being enclosed by square brackets) in order to retrieve data of a specific article as follows:

{{#visualdataquery:Data:Countries/Afghanistan
|schema=Country 
|?states/cities/name
|?states/cities/latitude
|?states/cities/longitude
|format=datatable 
}} 

or

{{#visualdataquery:710
|schema=Country 
|?states/cities/name
|?states/cities/latitude
|?states/cities/longitude
|format=datatable 
}} 

(this is especially useful in join queries —by which the result of a query is used as a condition for another query— or with the VisualData/API)

Logical operators

Conditions are concatenated by default using the AND operator. The OR operator is supported by using double pipes within the condition itself, as follows:

[[prop a::a||prop a:b]]

(this will match the property 'prop a' when its value is 'a' or 'b')

The same property can also be concatenated multiple times (using theAND operator) as follows:

[[prop a::!a]] [[prop a::!b]]

(this will match the property 'prop a' when its value is different from 'a' and 'b')

Special prefixes

Queries can also use the following special prefixes:

• Creation date (alias: CreationDate)
• Modification date (alias ModificationDate)

in order to query articles created or modified after, before, equal or different from a given date in any of the PHP's Supported Date and Time Formats. For instance:

[[Creation date >= 2025-01-01 00:00:00]]

will query (or will add such condition) all 2025 articles.

(this feature is used by the Datatable format to implement the datatables-synch parameter)

With the latest version (1.0.9) Creation/Modification date can be used also for sorting.

Printouts

In the specific dialect of VisualData (of course inherited from Semantic MediaWiki), a "printout" is a property path, therefore (technically) a json-pointer without array indexes and json-schema keywords. This way it is possible to easily reference nested property omitting technical details.

The printouts are indicated pre-pending a question mark to the parameter value:

|?states/cities/name
|?states/cities/latitude
|?states/cities/longitude

If no printouts are declared, the query will return all properties (including nested properties) of a given schema. (this however should be avoided since for large schemas the mysql query will exceed the number of supported joins)

Since version 1.0.8 it is also possible to specify an alternative name for the printouts especially used with the table or datatables result formats.

|?states/state_code=
|?states/name=State name
|?states/cities/name=City name
|?states/cities/latitude 
}}

The previous query will show the states column with name "State name", the cities column with header "City name", and while it will retrieve the "state_code" field for the use within templates, it won't be showed in the table.

The visualdataprint parser function as unnamed argument expects a page name or Help:Page_ID and is used to query a single page without further conditions

Categories

Categories related to articles to which the data are associated can be returned by the query using the categories=true parameter. Categories will then be available in templates with one of the following alias:

• categories
• _categories
• cats
• _cats

The same aliases can be used as printouts. For instance the following query

{{#visualdataquery:[[name::+]]  
|schema=Country 
|?name
|?region
|?categories
|format=datatable 
|template?name=Dynamic catalogue row
|datatables-searchPanes=true
|pagetitle=
|limit=100
|offset=0
|categories=true
}}

(source: https://wikisphere.org/wiki/Demo_VisualData/Dynamic_catalogue)

enables categories with |categories=true and displays the related field with ?categories (which in turn may contain an alias using ?categories=my categories

Format

Both the visualdataquery (and the visualdataprint) parser functions expect a format through which print the result. Find out more here.

Special properties aliases

Special properties like pagetitle, pageid, and categories (a future version of VisualData will also provide creationDate and modificationDate as printous) are available both from templates and as printouts via a number of aliases. Such aliases will be used only when a schema printout does not exist with the same name, so it is safe to have schema properties names "pagetitle", "pageid" and/or "categories" and in this case another alias must be used.

Here is a table with all the currently available aliases:

Parameters

Here are the available parameters for the visualdataquery parser function and their default values.