Should UIDs equal EIDs?
Should my UIDs (user ids) be the same as my EIDs (enterprise IDs) in Sakai?
This question was asked and answered on the sakai-dev email list.
Theoretically, it's valid for UIDs to equal EIDs, and some schools run just such a configuration. However, in general, EIDs are understood to be owned by an external system of record and as such are intended to be mutable, whereas UIDs are intended as opaque, immutable database keys. Thus, in an ideal world, EIDs are stored only once in the Sakai database, but UIDs can be stored repeatedly as pseudo-foreign keys. If it's actually true that your EIDs never ever change, then you could probably get away with generating SAKAI_USER_ID_MAP rows where USER_ID = EID, but without fully understanding the motivation for pre-populating those rows, I would generally advise against taking such risks (i.e., of scattering potentially mutable FKs around your database).
FWIW, /portal/site/~[EID] urls will resolve the correct MyWorkspace sites, even if UIDs != EIDs. But I understand that GUID-based MyWorkspace site IDs can be annoying in other contexts. There is a patch for this that makes it easier for admins to find MyWorkspace sites by EID.
