Redmine Project Types Relations

Self-related Relation¶

A relation between two objects of the same model (ProjectType or Project) is defined as ordered pair:

(a,b) != (b,a)

The left object of the pair is the superordinate (guest) and the right object is the subordinate (host).

• Project types uses superordinate and subordinate notation.
• Projects uses guest and host notation.

Resulting Rules concerning Data Persistence¶

1. An object cannot have a relation to itself: (a,a) or (b,b) .
2. An oject cannot have a subordinated relation to its superordinated object, what would cause a circular reference: (a,b) and (b,a) . That is, a relation is either (a,b) or (b,a), but not both. The preferred definition, what should be saved, is from superordinated object to subordinated object.
3. The pair (a,b) is uniqe.