The screenshots now show the whole page rather than a cropped viewport, and the
configuration table is included so the three variables in the grid can be
traced to the three rows that define them.
Three screenshots from the EDIT screen: the derived columns in the grid, a
filter on a character derived column, and a filter on a numeric one. Plus a
short 'how it works' explaining that the statements go into a DATA step view
because a WHERE cannot see a variable created in the same step.
Each row lists every input the expression uses, physical columns and derived
variables alike. No sequence number to maintain; statements are emitted in
dependency order and a cycle is rejected.
A derived variable can now be built on one with a lower VARIABLE_ORDER, so
the pages describe the order column, the ordered rule (replacing the
self-contained one) and a chained example.
Review follow-up: /dc-userguide/#editor (the heading is 'Editor'), the
reserved names include VAR_TXFROM/VAR_TXTO/VAR_PROCESSED, and derived
columns are not shown in VIEW or downloads though a saved filter on one
still applies there.
New Configuration page explaining derived (computed) variables: what they
are, how to configure them in MPE_DERIVED, how filtering works, the rules
and limits (expressions only, self-contained, read-only, not stored), and
the data-exposure and performance notes.
New MPE_DERIVED table page, registered in the Table Guide nav.
dc