buildingSMART Forums

Model View Definition structure

Trying to develop a MVD using IfcDoc, I am wondering what is the difference, if one entity/concept is listed under another table definition(another entity) as a column definition or when it is seperately listed as a table definition.
As an example:
In “General Usage” MVD , model Library information is under IfcProject listing, whereas in “Design Transfer” it is under IfcProjectLibrary.
Can someone explain the difference briefly , advantages, disadvantages of each very briefly please.