fun <T> withConnection(url: String, user: String, password: String, body: (db: Database) -> T): T
Execute a body of code with a new JDBC connection that is held within a Database instance.
If the client code makes that Database instance available to other threads, it is
the client's responsibility do do any needed synchronization. When the code body exits,
the connection is closed, and the Database instance is no longer usable.
Usage example:
Database.withConnection("jdbc:h2:mem:test", "root", "") { db ->
various operations on db
}