Schema Hierarchy
The schema hierarchy is a hierarchy structure category that differs from the structure category hierarchy
in the assignment of the level numbers.
In the case of the structure category hierarchy
, the system pulls the levels in numerical order.
In the case of the structure category schema hierarchy
, the level number is a designation that does not contain the numerical order of the levels but has significance as a number in itself. The specified value of the level number stands for the number of characters
that defines the object of the level:
Level number |
Number of characters |
Object |
|---|---|---|
Level 1: 3 |
3 characters |
AAA |
Level 2: 5 |
5 characters |
AAA BB |
Level 3: 9 |
9 characters |
AAA BB CCCC |
Note that the characters of the object at the upper level must be replicated at a subordinate level so that the assignment can be recognized. Level 2 objects with the designation AA1 BB, for example, cannot be assigned here to a higher level.
Unlike hierarchy structures, the digit here has both a classification and semantic significance.