Richard Holland wrote:
Originally, MartBuilder would stick a number on the end of a column
when it thought there was a naming clash between that column and
another one on the same table. The number prevents the naming clash.
(e.g. if you merge two tables which both have a column called 'name'
into the same mart table, you will have to rename one of them to be
able to include both of them, and so MartBuilder sticks a number on).
However this proved to cause problems when tables were added or
removed from existing marts, causing the order in which columns were
merged to change. This also would change the order in which the
numbers were added - so you could end up with your original mart
columns name_2 and name_3 being swapped around and pointing to
different things. If you didn't notice (it was hard to spot), then
when you copied over your existing MartEditor config, you'd find the
data in the associated filters/attributes would be swapped around
also.
To resolve this, it was decided that every column should by default
get a unique table identifier suffixed to it. This identifier is
arbitrarily generated but is consistent, and every time you build a
mart against the same schema, you will see the same numeric suffixes.
This prevents both naming clashes AND the problem with numbers getting
swapped around during schema changes.
You can rename any column at the MartBuilder stage by double-clicking
on it and typing a new name. At the MartEditor stage, the display and
internal names are by default the column name, but again these can
both be changed to anything you like as long as it continues to be
unique.
Hope this helps.
Thanks for comprehensive answer. I did help a lot :).
--
Henrikki Almusa
