V2 diagram (24 July 2021)

[DanielLoth]

Hi @Derek-Asirvadem ,

I've attempted to improve the diagram based on previous conversation.

Link to view the PDF version of the diagram: https://github.com/DanielLoth/ShootingClubDatabase/blob/add-diagram-2021-07-24/Diagrams/2021-07-24%20-%20Data%20model%20V2.pdf

[Derek-Asirvadem]

@DanielLoth

Nice work.

1. What is the distinction between User and Person ?
2. In the V1 model,
   • it is not clear what columns are PK (I appreciate it is not IDEF1X). So it is not clear whether the columns in a child are Identifying or not.
   • Second point. However it does appear to be clear from the position you have laid out the hierarchy, but then you have drawn some tables that are Reference only, which are Non-Identifying relations, as subordinates ... but Reference tables (Non-Identifying relations) do not define the hierarchy (positioning), only Identifying relations do.
   • The vertical hierarchy consists of Identifying relations.
3. Both V1 and V2 models. Another way of explaining all that is, you have no dashed lines. Which means you are not differentiating Identifying vs Non-Identifying relations.
4. The relation names are the Constraint names (you have copied well). That is correct if model is showing the Physical view. Whereas in the Logical view of the same model, we need the VerbPhrase.
   Again, you have been good at throwing yourself at the task, but you are thinking bottom-up, both identifying and defining the physical objects that you will need.
5. Protocol.
   How about this, in terms of responding to each others DMs. Any DM you produce should be even-numbered; any that I produce should be odd. That way we can keep track of the progress. Of course, that does not mean that every number will be used.
6. When you erect a symbolic (semantic; logic) diagram, the symbols must be uniform, not different sizes. Yes, I understand there is a difficulty re attaching lines; and another when the text is wide.

Version Number
Strictly we are in Version 0 because it is a first crack (Version 1 would be whatever you actually implement when V0 is stable; physical; etc.) So your V2 is V0.2. Second full stops cause problems if it is in the file name, when necessary an underscore can be substituted.

Cheers
Derek