SQL supports hidden columns: columns that are only included in a projection if explicitly requested. An example of this is the rowid column that is created on tables without explicitly primary keys.

Currently, there is no way to get a hidden column on a user-defined table: it's only possible if you manually set the hidden boolean in the table descriptor, by editing the CockroachDB source code

Issue description

Go 1.15 will introduce a new Validator interface, which may be implemented by Conn to allow drivers to signal if a connection is valid or if it should be discarded:

https://tip.golang.org/pkg/database/sql/driver/#Validator

Hello Philip!
I think there is an issue with this part of the code of rqlite (store/store.go).

func (s *Store) Database(leader bool) ([]byte, error) {
	if leader && s.raft.State() != raft.Leader {
		return nil, ErrNotLeader
	}
	// Ensure only one snapshot can take place at once, and block all queries.
	s.mu.Lock()
	defer s.mu.Unlock()

	f, err := ioutil.TempFile("", "rqlilte-snap-

I'm not sure how feasible this may be, but the old logparser program from Microsoft supported queries like

Select * from test.csv

And it would read from test.csv, without needing any config files.

What would you like to be added:

Currently config uses one file per environment (eg. dev, staging, prod, etc) we should move to a multi-file config where we have one folder per environment and config values can be split across multiple files within this folder.

Why is this needed:

For setups where there are