After mass structure updates, some views/procedures became invalid.
So I just recompiled them with:
exec dbms_utility.compile_schema( USER )
But after that, all function-based indexes, which before were in a good state, became broken, and SQL statements against those tables failed. And that is the problem.
Example of such indexes:
CREATE INDEX DOCUMENTS_NMBR_UCN_FIDX ON DOCUMENTS(Str2Number(NUMBER_UCN)); CREATE INDEX DOCUMENTS_DATE_FIDX ON DOCUMENTS(Date2Number(REG_DATE));
Why did that happen?