Mapping Functions or Activities to child IDEF0 diagrams
Refer to these best practices when mapping Functions or Activities to child IDEF0 diagrams.
Number of Functions/Activities on Child IDEF0 Diagram
According to the IDEF0 method, no child diagram IDEF0 diagram can contain fewer than three nor more than six Function/Activity symbols. If you need more than six boxes in a child diagram, create an additional child diagram subordinate to the original child diagram. If you need fewer than three boxes, create one or two additional Function/Activities on the parent diagram rather than creating a child diagram.
Node Numbers
A node number beneath the parent Function/Activity gives a reference number for the child diagram. This number is called the Detail Reference Expression (DRE.)
The IDEF0 method assigns DRE numbers using a node numbering scheme:
▪The first diagram, the Context or A-0 diagram, contains one box, numbered 0. This diagram becomes parent to the first child diagram. Its DRE number is A-0 (therefore the name, A-0 diagram).
▪The first child diagram, like all child IDEF0 diagrams, can contain from three to six boxes, numbered from left to right, starting at 1. These symbols are denoted A1 thru A6.
▪For child diagrams on subsequent levels, symbol numbers are formed by appending the number of the Parent box, to the number of the diagram containing that Parent box. So if you create a child IDEF0 diagram for A1, it would have symbols on it named A11 thru A16 (if six symbols were used on the child diagram). A child diagram for symbol A2 would have symbols on it named A21 thru A26.
Using this node numbering scheme, it is possible to summarize a model in the form of either a written outline or a tree diagram. The outline form is called a node index.
Note To automatically number symbols on IDEF0 child (or constraint) diagrams, turn on auto-numbering:
▪Select Tools > Preferences, and then select Numbering.
▪With a Function/Activity symbol on an IDEF0 diagram selected, choose Format, Symbol Format, Symbol Style. In the Symbol Style dialog, make sure Allow, Auto Name is toggled on.