Teradata Mapping Manager issues - response (3) by ccurry

If you are still using TMM 2.1.3 and saving mapping without map notes, that is the known bug so the USI error is expected. If you are saving with map notes and still getting USI error, then you have apparently found another situation that triggers the same bug. If you cannot finish the training with my earlier suggestions then I can only recommend that you upgrade to the latest TMM version (2.1.4 as of today) which should fix the USI-error bug.
Regarding data models, I am not able to share the ER diagram of the metadata repository for a number of reasons. One of the most important reasons is that we do not want to imply that we support any direct access of TMM metadata tables and, even more importantly, we cannot support or encourage any direct modification of metadata in the repository. If anyone were to directly modify the metadata table contents, there is a good chance that they would corrupt the metadata such that TMM would not be able to use the metadata. BTW, some of the table and column comments are out of date or just plain wrong, so you cannot count on those for proper metadata definition.
If a TMM bug corrupts the metadata repository (I can only recall one case where this actually happened), and it is something other than the training repository, then post your problem and if I am still the product owner for TMM I will try to recover your metadata and get you running again. Teradata cannot guarantee that this will happen, but that is my recommended remediation path if you have a real corruption problem.
We do provide a published set of TD Views of the repository that anyone can use to read the metadata, as documented in the TMM in-app help system. It is believed that the table/column comments for those published views and the associated help topics are accurate definitions of the metadata.