Crystal Pool:Fundamental concepts
This wiki site uses Wikibase, the essential part of Wikidata, to organize the structured data, including the data of books, authors, characters in the fiction, etc. For basic concepts on Wikibase, see the introduction on Wikidata. You may also take a look at the tours provided on Wikidata.
As of 2017-12, Wikibase does not support references to entities on a foreign site (e.g. referring to a Wikidata entity from Crystal Pool, vice versa), thus the property Wikidata item ID (P2) is introduced to mark the entities that are imported from Wikidata with their original entity IDs. See Universe (Q2) for an example of this.
Please do not modify the claims on these entities with your hands, as they are managed by synchronization scripts.
Wikibase has a constraint called inverse constraint (wd:Q21510855), that requires the entities, used as value in a claim, should also have a claim, with the inverse property, that points back to the entity that declared the claim. There are related discussions on Wikidata on how to manage inverse properties.
Upon the initiation of the website, the creator has the hope that, by reducing the redundancy, the burden of keeping the consistency among the items can be lifted. Thus he decided not to introduce any of the inverse properties. For example, wd:P629 and wd:P747 are a pair of inverse properties. To reduce the redundancy, here we only keep edition or translation of (P52), the corresponding entity for wd:P629.
The ability of querying for the inverse of a property (i.e. find the entities whose certain property has the given value) should be implemented via other means. However it's not available yet. Nonetheless, you may use the What links here link in the sidebar to help you determine what entities used the current one.