keySequence definition overloaded #12
Description
https://temeta.github.io/define-json/slots/keySequence/
"Ordered list of Items that define the dataset key structure for sorting and uniqueness. Each entry is an OID reference to an Item in the items array. Order determines sorting precedence, merge operations, and record uniqueness. These are allowed to be null, unlike stricter dataset dimensions or primary keys."
I think we have two different concepts "sorting and uniqueness" that we shouldn't mix.
a. For uniqueness, I wonder why we need an ordered list. It is nice for visualization, not for ensuring uniqueness.
b. For sorting, we may want to sort by items that are not part of the key.