advanced-search-user-docs.md

Advanced Search Component

Introduction

The AdvancedSearchComponent allows for the creation of complex queries using a graphical widget. The widget's contents are then turned into a string representing a Gravsearch (SPARQL) query to be sent to DSP-API.

A query consists of the following elements:

• ontology (data model) selection
• selection of a resource class belonging to the selected ontology (optional)
• specification of properties, comparison operators, and values (optional).

Although selection of a resource or a property or both are optional, either a resource class has to be selected or at least one property has to be specified, otherwise the query is not considered valid and cannot be submitted.

Comparison Operators

Depending on the value type of the chosen property, one or more of the following comparison operators can be selected:

• is equal to: value equality: same number, exact same string, overlap of date periods, same target resource.
• is not equal to: value inequality: not same number, not exact same string, no overlap of date periods, not same target resource.
• is greater than: value comparison: number is greater than search value, date period begins after search value.
• is greater than or equal to value equality / value comparison: number is equal to or greater than search value, overlap of date periods or date period begins after search value.
• is less than: value comparison: number is less than search value, date period ends before search value.
• is less than or equal to: value equality / value comparison: number is equal to or less than search value, overlap of date periods or date period ends before search value.
• exists: value for the given property exists.
• is like: search value is contained in a text using the SPARQL REGEX function (supports regular expressions).
• matches:
  • text property: search value matches the text (Lucene Query Parser Syntax).
  • linking property: matches the specified linked resource.

Search Examples

Regular Expressions (is like)

The is like operator lets the user search for texts that are like the search value via the support of regular expressions In this example, all books are found whose title contains "Narrenschiff" followed by a space and some other characters like "(lat.)" or "(dt.)".

For general information about regular expressions see this interactive tutorial.

Lucene Parser Syntax (matches)

Used with a text property, the matches operator lets the user search for texts that match the search value, supporting Lucene Query Parser Syntax. In this example, all persons are found whose names contain "Ja" and "ob" with a character in between (represented by the wildcard "?"). This search finds "Jacob" as well as "Jakob".

Note the difference between regular expressions and Lucene parser syntax!

Specifying a Linked Resource (matches)

Used with a linking property, the matches operator lets the user search for a linked resource that matches the specified properties. In this example, the user writes a query looking for all letters that have an author that:

1. was born after January 1st 1650
2. whose family name is "Bernoulli"

This is different from the "is equal to" operator that lets the user specify a certain person (selected from a list).