bluechips/model/__init__.py

   1 """The application's model objects"""
   2 import sqlalchemy as sa
   3 from sqlalchemy import orm
   4
   5 from bluechips.model import meta
   6 from bluechips.model import types
   7
   8 def init_model(engine):
   9     """Call me before using any of the tables or classes in the model"""
  10
  11     sm = orm.sessionmaker(autoflush=True, transactional=True, bind=engine)
  12
  13     meta.engine = engine
  14     meta.Session = orm.scoped_session(sm)
  15
  16 ### Database Schemas ###
  17
  18 users = sa.Table('users', meta.metadata,
  19                  sa.Column('id', sa.types.Integer, primary_key=True),
  20                  sa.Column('username', sa.types.Unicode(32), nullable=False),
  21                  sa.Column('name', sa.types.Unicode(64)),
  22                  sa.Column('resident', sa.types.Boolean, default=True)
  23                  )
  24
  25 expenditures = sa.Table('expenditures', meta.metadata,
  26                         sa.Column('id', sa.types.Integer, primary_key=True),
  27                         sa.Column('spender_id', sa.types.Integer,
  28                                   sa.ForeignKey('users.id'), nullable=False),
  29                         sa.Column('amount', types.Currency, nullable=False),
  30                         sa.Column('description', sa.types.Text),
  31                         sa.Column('date', sa.types.Date, default=sa.func.now),
  32                         sa.Column('entered_time', sa.types.DateTime,
  33                                   default=sa.func.now)
  34                         )
  35
  36 splits = sa.Table('splits', meta.metadata,
  37                   sa.Column('id', sa.types.Integer, primary_key=True),
  38                   sa.Column('expenditure_id', sa.types.Integer,
  39                             sa.ForeignKey('expenditures.id'), nullable=False),
  40                   sa.Column('user_id', sa.types.Integer,
  41                             sa.ForeignKey('users.id'), nullable=False),
  42                   sa.Column('share', types.Currency, nullable=False)
  43                   )
  44
  45 subitems = sa.Table('subitems', meta.metadata,
  46                     sa.Column('id', sa.types.Integer, primary_key=True),
  47                     sa.Column('expenditure_id', sa.types.Integer,
  48                               sa.ForeignKey('expenditures.id'), nullable=False),
  49                     sa.Column('user_id', sa.types.Integer,
  50                               sa.ForeignKey('users.id'), nullable=False),
  51                     sa.Column('amount', types.Currency, nullable=False)
  52                     )
  53
  54 transfers = sa.Table('transfers', meta.metadata,
  55                      sa.Column('id', sa.types.Integer, primary_key=True),
  56                      sa.Column('debtor_id', sa.types.Integer,
  57                                sa.ForeignKey('users.id'), nullable=False),
  58                      sa.Column('creditor_id', sa.types.Integer,
  59                                sa.ForeignKey('users.id'), nullable=False),
  60                      sa.Column('amount', types.Currency, nullable=False),
  61                      sa.Column('description', sa.Text, default=None),
  62                      sa.Column('date', sa.types.Date, default=sa.func.now),
  63                      sa.Column('entered_time', sa.types.DateTime,
  64                                default=sa.func.now)
  65                      )
  66
  67 ### ORM Classes ###
  68
  69 class User(object):
  70     def __repr__(self):
  71         return '<User: %s>' % (self.username)
  72
  73 class Expenditure(object):
  74     def __repr__(self):
  75         return '<Expenditure: spender: %s spent: %s>' % (self.spender,
  76                                                          self.amount)
  77
  78 class Split(object):
  79     def __repr__(self):
  80         return '<Split: expense: %s user: %s share: %s>' % (self.expenditure,
  81                                                             self.user,
  82                                                             self.share)
  83
  84 class Subitem(object):
  85     def __repr__(self):
  86         return '<Subitem: expense: %s user: %s cost: %s>' % (self.expense,
  87                                                              self.user,
  88                                                              self.amount)
  89
  90 class Transfer(object):
  91     def __repr__(self):
  92         return '<Transfer: from %s to %s for %s>' % (self.debtor,
  93                                                      self.creditor,
  94                                                      self.amount)
  95
  96 ### DB/Class Mapping ###
  97
  98 orm.mapper(User, users)
  99
 100 orm.mapper(Expenditure, expenditures, properties={
 101         'spender': orm.relation(User, backref='expenditures')
 102 })
 103
 104 orm.mapper(Split, splits, properties={
 105         'expenditure': orm.relation(Expenditure, backref='splits'),
 106         'user': orm.relation(User)
 107 })
 108
 109 orm.mapper(Subitem, subitems, properties={
 110         'expenditure': orm.relation(Expenditure, backref='subitems'),
 111         'user': orm.relation(User)
 112 })
 113
 114 orm.mapper(Transfer, transfers, properties={
 115         'debtor': orm.relation(User,
 116                                primaryjoin=(transfers.c.debtor_id==\
 117                                                 users.c.id)),
 118         'creditor': orm.relation(User,
 119                                  primaryjoin=(transfers.c.creditor_id==\
 120                                                   users.c.id))
 121 })
 122
 123 __all__ = [users, expenditures, splits, subitems, transfers,
 124            User, Expenditure, Split, Subitem, Transfer,
 125            meta]