jdbc:connect functions should not be sequential

[Matthias Brantner]

The jdbc module's connect functions should not be sequential. Instead, the functions should be marked as nondeterministic because they don't have side-effects.

Otherwise, it's not possible to implement a non-sequential query if one just wants to query a jdbc data source (e.g. execute-query is already non-sequential).

[Chris Hillery (ceejatec)]

execute-query() should be marked as nondeterministic.

execute-update() should be marked sequential.

Also, the corresponding changes should be made (as necessary) to the oracle-nosql-db, sqlite, and couchbase modules.

[Chris Hillery (ceejatec)]

FYI, after some discussion with Matthias, I have changed the sqlite module (since the update merge proposal was done for it anyway).

Previously, all functions were sequential. Now, the following functions are nondeterministic:

connect()
is-connected()
execute-query()
metadata()
prepare-statement()

In particular, we left all the set-XXX() functions sequential.

We couldn't decide whether it was safe to make execute-query-prepared() nondeterministic or not, but to me at least, it seemed reasonable that if set-XXX() is sequential, execute-query-prepared() needs to be sequential as well. So, we took the more conservative approach and left it sequential.