attach abstract method
Some drivers can attach other open databases and reference them by alias
(i.e.: first you attach('foo.db')
then you can write SQL queries like
select * from foo.bars
. We keep track of attached databases and their
aliases, so we can map the table namespaces in SQL queries to their real
database names and thus emit and handle notifications to and from them.
Implementation
void attach(DbName dbName, String dbAlias);