From Dwayne Wright PMP
Certified FileMaker Developer
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Ok, let me start off by saying ... that I am not talking about ... those little lines around your eyes that come from staring at the Define Relationship Graph dialog box too long.
Various parts of the relationship graph area carry over (rather loosely I might add) from elements in an entity relationship diagram. An Entity Relationship Diagram (ER Diagram for short) provides a method to document the entities in your database solution, the fields/attributes that define an entity and the relationships between them. In many ways, the FileMaker relationship graph does this as well and much more. If you look closely to where the relationship line connects to the table occurrence box, it spreads out in three prongs (looking somewhat like a crows foot).
Whether the line connects to the table occurrence via a straight line connection or via a crows foot depends upon the cardinality of the relationship. Once again, as a refresher, relationship cardinality refers to the type of relationship such as one to one, one to many and many to many. A crows foot would be an indication the connection to that table occurrence can include multiple records in that table occurrence. So the flow towards that table occurrence is likely a one to many or a many to many relationship. This isn't a guarantee this is indeed true for every record using that relationship but it is a good indication this is true.
HOW SUBTLE THE CHANGES
Look at the two below images from the FileMaker relationship graph, see if you can see what is different and know what prompted the change?
Notice the crows feet do not appear on the patient side of the table occurrence, denoting that a charge record can only be associated to one patient. How does this happen you might be wondering?
The setting of the patient number in the patient table to be an auto enter serial number triggered it!
More info about the author and FileMaker in general, contact me at firstname.lastname@example.org.
© 2007 - Dwayne Wright - dwaynewright.com
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