class declaration begins here.
All the metadata—schema, tables, and
object-relational mappings—are declared inside
this class. The mapped classes are also
inside this class; the author found this
somewhat disturbing at first, but it makes perfect sense.
For example, if a user has an instance
CBCData, they can refer to the
circles table as
db.circles_table or as
CBCData.circles_table. Similarly, they
can refer to the constructor the class mapped to that
table either as
# - - - - - c l a s s C B C D a t a class CBCData(object): '''Represents the entire Christmas Bird Count database. '''