Since column PROJECTS.UUID was added in 6.0 by
SONAR-7738 it has a non unique index called PROJECTS_UUIDS on all SGDBs but H2.
Unfortunately, the index is correct on H2 and should be unique as the code has been assuming it is since forever.
The cause of this situation is probably to find in the usage of Ruby at the time and the fact database used to unit test DB changes was not initialized with Ruby by with a static script.
Luckily, SQ code is consistent enough that it apparently never inserted two rows with the same UUID in table PROJECTS and/or we never tried and retrieve those rows.