Any node in any library (except document libraries) has the ability
to classify whatever items it contains. That is, any item placed in that
library node, also referred to as a class, acquires from that class a
set of attributes that define the class. For example, if there is a class
node (such as a part family) called "Screws" in a part library, and Screws
have attributes "Thread Pitch" and "Length," then any part that is inserted
into the Screws part family "becomes" a screw and therefore acquires
the attributes of Screws, which are Thread Pitch and Length.
Library nodes, therefore, define classes by dictating a set of attributes
that make up that class.
Attributes associated with a class are clustered into groups.
Any given class can have any number of attribute groups. For example,
the class Screws could pick up an existing Pricing attribute group, as
well as some other attribute group--which could be called TpiAndLen--that
contains Thread Pitch and Length.
Attribute groups are inherited from a class by its children. Attribute
groups are just what their name implies: a list of standard attributes
created and grouped together under a descriptive name. For example, a
librarian might take attributes "Manufacturing Cost," "Dealer Cost,"
"Retail Price," and "Minimum Advertised Price" and group them together
into an attribute group named "Pricing."
Attribute groups are used in classification with library nodes that
represent classes. Attribute groups have no other use beyond classification.
The attribute groups that define a class become part of the classified
items that get put into that class. So if Part PT-00059 Rev A gets put
into "Screws," that particular part instance acquires the attribute groups
dictated by Screws and you can then see and edit those attributes. The
Screws part family itself does not instantiate the attributes in any
way that you can view or edit values. For example, you could not make
the length of Screws be 2in, but you can make the length of PT-00059
Rev A be 2in.
When PT-00059 Rev A gets classified as Screws, it acquires the attributes
of Screws but does not automatically acquire any values for those attributes.
IP Classification uses the default value
for that attribute (typically zero or an empty string), and you can then
edit the Part to enter specific values.