-- A pin names the module as well as the node (novox/hq #258).
--
-- 0008 said "not a module: the same module on two machines is two answers, and which machine is the
-- whole question". Half right. Two modules on one machine can both answer a provision — public-acme
-- and step-ca both offer acme-ca on novox — and then which *module* is the whole question, and a
-- node alone cannot ask it. The resolver, given a node that answered twice, took the last one listed.
--
-- A provider is a (node, module) pair (design 23), and a pin names the pair. Nullable, so a record
-- made before this was asked keeps meaning what it meant: honoured while that node answers once,
-- refused with the module asked for when it answers twice.
alter table provision_pin add column module text;