Work with databases.

: OpenDB ( addr u fam -- dbOR )
Find and open a database.
addr u - name
fam - open mode
dbOR - dbOpenRef

: CloseDB ( dbOR -- )
Close a database.

: OpenRecord ( dbOR i -- addr u )
Open record number i and return its address and length (addr u).

: CloseRecord ( dbOR i -- )
Close record number i.
