predicate
Retrieve information about predicates. Predicates are the labels on edges (connections between resources) that give
meaning to an edge. An example is the predicate "author" which refers to the authors of an article. Predicates form
together with the referring and the referred page a triple {subject, predicate, object}.
Each predicate has a list of valid subject categories and valid object categories. This is used to filter the list of predicates in the admin edit page, and also to filter the list of found potential objects when making a connection.
A full predicate definition can be fetched by name or id with:
{{ m.predicate.author }}
{{ m.predicate[104] }}Which both return a property list with information about the predicate. The property list contains all page properties and the properties: "pred" which is the atomic predicate name, "subject" which is a list of valid subject categories and "object" with is a list of valid object categories.
The following m_predicate model properties are available in templates:
| Property | Description | Example value |
|---|---|---|
| all | Return a property list of all predicates. Keys are the atomic predicate name, values are property lists with information about the predicate. The property list contains all page properties and the properties: "pred" which is the atomic predicate name, "subject" which is a list of valid subject categories and "object" with is a list of valid object categories. | [{about, [{pred,about}, {subject,[104]}, {object,[]}, {id,300}, ...]}] |
| object_category | Used to derive the list of valid object categories for a predicate. Example usage: m.predicate.object_category.author Note: Each id is a 1-tuple. | [{104}, ...] |
| subject_category | Used to derive the list of valid subject categories for a predicate. Example usage: m.predicate.subject_category.author Note: Each id is a 1-tuple. | [{674}, ...] |
Available Model API Paths
| Method | Path pattern | Description |
|---|---|---|
get | / | Return full predicate definition list (same as /all), keyed by predicate name. No further lookups. |
get | /all/... | Return all predicate definitions with allowed subject/object categories and predicate metadata. |
get | /is_used/+pred/... | Return whether predicate +pred is referenced by at least one row in edge. |
get | /object_resources/+key/... | Return visible/published resources allowed as objects for predicate +key, bucketed by matching valid object category and title-sorted. |
get | /object_category/+key/... | Return list of valid object category ids for predicate +key (empty means unrestricted). |
get | /subject_category/+key/... | Return list of valid subject category ids for predicate +key (empty means unrestricted). |
get | /is_valid_object_in_category/+predicate/+category/... | Return whether category +category is valid for objects of +predicate, including inverse ancestor matching fallback. |
get | /is_valid_object_subcategory/+predicate/+category/... | Return whether +category is valid object category for +predicate, allowing ancestor matches (IsSubcats=true). |
get | /is_valid_object_category/+predicate/+category/... | Return whether +category is directly valid object category for +predicate (IsSubcats=false). |
get | /is_valid_subject_subcategory/+predicate/+category/... | Return whether +category is valid subject category for +predicate, including subject ancestor/subcategory matching (IsSubcats=true). |
get | /is_valid_subject_category/+predicate/+category/... | Return whether +category is directly valid subject category for +predicate (IsSubcats=false). |
get | /predicate/+key/... | Return predicate definition for +key (id/name), including pred, subject, and object fields; undefined if unknown. |
get | /+key/... | Alias for /predicate/+key/...; return predicate definition for +key or undefined. |
/+name marks a variable path segment. A trailing /... means extra path segments are accepted for further lookups.