Submitted by: @pavel-zotov

There is something strange in error message when i want to create index for NON-existent table.
Consider following script (doing it on empty database):

SQL> create index no_such_index on no_such_table( some_fantastic_column );
Statement failed, SQLSTATE = 42000
unsuccessful metadata update
-Unknown columns in index NO_SUCH_INDEX
SQL>

Why "unknown COLUMNS" are mentioned here ? I just used wrong name of TABLE rather than column(s) of it.

IMO, much better to raise SQLSTATE = 42S02 ("-Table unknown"), similar to this case:
SQL> select * from no_such_table;
Statement failed, SQLSTATE = 42S02
Dynamic SQL Error
-SQL error code = -204
-Table unknown
-NO_SUCH_TABLE