Completion Queries
Completion queries are send to the backend to retrieve the completion suggestions. These Queries are individual for each knowledgebase. The user has to define a query template for each type of online-completion.
Completion query anatomy
Each completion query MUST result must contain the following variables.
| Variable | Content | Example |
|---|---|---|
?qlue_ls_entity |
RDF tem, value to be completed | \<book_1> |
?qlue_ls_label |
representation of completion item | book title |
?qlue_ls_detail |
description of the completion item | Book from author ... |
Templating engine
The templates are rendered by tera, a templating engine. It provides:
- Control structures, like for and if
- Data manipulation, like filters, tests and functions
Template Context
Each template has the following variables available:
| Variable | Content | Example |
|---|---|---|
| prefixes | list of prefix, iri pairs | [("rdfs", "http://www.w3.org/2000/01/rdf-schema#"), ("rdf","http://www.w3.org/1999/02/22-rdf-syntax-ns#")] |
| subject | subject of current triple | "?sub" |
| local_context | Query pattern for the current triple | "?sub ?qlue_ls_entity []" |
| context | Query pattern for the constrainig part of the query | "?sub rdfs:type |
Custom Tests
Tests can be used against an expression to check some condition. There are many build in tests but also some custom SPARQL specific ones:
variable
Takes a string and checks if its a SPARQL variable or not.
Example:
{% if subject is variable %}
Subject is a variable
{% elif %}
Subject is not a variable
{% endif %}