Cover has tightly
coupled work objects whereas folder has loosely coupled.
Cover has one-one , one-many relationships
with its work objects - meaning that a work object only one cover and a cover can
have many work objects.
Folder has many-many relationship.
A cover can have a cover but a cover can NEVER
have a folder in it. Folder can have covers.
Limitations for cover
A cover can hold upto 20 work objects.
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