Document unique identifiers

[maurolepore]

(via https://goo.gl/Fn4TDE)

Suzanne explained which variables identify uniquely each row of the following data sets:

• ViewFullTable
• tree tables
• stem tables

A key to clarify my original consusion was this:

In the OLD version of the BCI R tables, StemID refers to the Stemnumber that is in ViewFullTable, not StemID. In all the NEW R tables, is unique.

In conclusion

Table: unique identifier
-------------------------
R Tree tables:  TreeID
R Stem tables:  StemID
ViewFullTable:  DBHID

This explains why StemID is not a unique identifier of ViewFullTable:

StemID uniquely identifies all stems. DBHID uniquely identifies all dbh measurements. ... If you are looking for a unique identifier in ViewFullTable, DBHID is the unique identifier. That is because a StemID can be measured several times, once for each census that it is alive.

What I need to do

I need to update all packages that use OLD data, where Stem tables lack a unique identifier.

One cheap solution is to fix the variable StemID to make it indeed a unique identifier. And document this action well. This should work well for datas ets which purpose is only demonstration, not the accuracy of the data.

Another more expensive solution is to add a NEW version of the BCI data, and maybe remove the OLD version (again, NEW and OLD here mean with or without a unique identifier for the Stem tables).