Schema Evolution publication categorizer

One core feature of EVE is Evolvable-SQL (ESQL),
an extension of SQL that allows the view
definer to express preferences for view evolution. Using
E-SQL, a user defining a view can specify what information
is indispensable, what information is replaceable
by similar information from other ISs, and
whether a changing view extent is acceptable. This is
done by attaching preference parameters to elements
of the view query. This then is the key to evolving a
view by rewriting its view definition into a possibly
non-equivalent one that still preserves the user’s
intended semantics.