Link Filters

Link filters are used to pick certain links between terms from a collection of links between terms. Note that links are different kinds of objects than terms. Links represent relationships between terms.

In this guide, links are usually written in the form

child_term -relation-> parent_term

So if there is an is_a relationship between "heart development" and "development", that link would be written as

"heart development" -is_a-> "development"

The Link Filter Interface

To enable link filtering in a user configurable filter designer, click the "Advanced" tab and make sure that "Link filtering" is enabled and "Keyword filtering" is disabled. (The "Link filtering" box cannot be clicked until "Keyword filtering" is turned off).

It is possible to have term filtering and link filtering enabled at the same time. If both are enabled at once, tabs will appear at the top of the interface so you can switch between the term filter and link filter controls.

The link filter interface looks like this:

Notice the field labeled "link facet". Besides this new field, the link filter interface looks exactly like the term filter interface.

The link facet determines what characteristics of the link will be considered when filtering. There are 4 possible link facets:

If any of the first three facets (child, type, or parent) are selected, the filter behaves just like a term filter. The NOT, Aspect, Attribute, Comparison, and Value fields are specified to select the desired terms, and the links whose appropriate facets match the filter will be matched.

If the Self facet is selected, however, a special set of link-specific attributes becomes available.

Link-Specific Attributes

The following attributes are available when the Self facet has been selected:

Special Behavior of the Search Aspect

If the Self facet is selected, search aspects work a little differently. In a term filter, the search aspect specifies an alternate collection of related terms to find a match. In a link filter, the search aspect specifies an alternate collection of related links.

For example, when the Self aspect is selected, the ancestor aspect searches all the ancestor links (NOT ancestor terms) to find a match.