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('date', sa.types.Date, default=sa.func.now),
  31                         sa.Column('entered_time', sa.types.DateTime,
  32                                   default=sa.func.now)
  33                         )
  34
  35 splits = sa.Table('splits', meta.metadata,
  36                   sa.Column('id', sa.types.Integer, primary_key=True),
  37                   sa.Column('expenditure_id', sa.types.Integer,
  38                             sa.ForeignKey('expenditures.id'), nullable=False),
  39                   sa.Column('user_id', sa.types.Integer,
  40                             sa.ForeignKey('users.id'), nullable=False),
  41                   sa.Column('share', sa.types.Integer, nullable=False)
  42                   )
  43
  44 subitems = sa.Table('subitems', meta.metadata,
  45                     sa.Column('id', sa.types.Integer, primary_key=True),
  46                     sa.Column('expenditure_id', sa.types.Integer,
  47                               sa.ForeignKey('expenditures.id'), nullable=False),
  48                     sa.Column('user_id', sa.types.Integer,
  49                               sa.ForeignKey('users.id'), nullable=False),
  50                     sa.Column('amount', types.Currency, nullable=False)
  51                     )
  52
  53 transfers = sa.Table('transfers', meta.metadata,
  54                      sa.Column('id', sa.types.Integer, primary_key=True),
  55                      sa.Column('debtor_id', sa.types.Integer,
  56                                sa.ForeignKey('users.id'), nullable=False),
  57                      sa.Column('creditor_id', sa.types.Integer,
  58                                sa.ForeignKey('users.id'), nullable=False),
  59                      sa.Column('amount', types.Currency, nullable=False),
  60                      sa.Column('date', sa.types.Date, default=sa.func.now),
  61                      sa.Column('entered_time', sa.types.DateTime,
  62                                default=sa.func.now),
  63                      sa.Column('desc', sa.Text, default=None)
  64                      )
  65
  66 ### ORM Classes ###
  67
  68 class User(object):
  69     def __repr__(self):
  70         return '<User: %w>' % (self.username)
  71
  72 class Expenditure(object):
  73     def __repr__(self):
  74         return '<Expenditure: spender: %s spent: %s>' % (self.spender,
  75                                                self.amount)
  76
  77 class Split(object):
  78     def __repr__(self):
  79         return '<Split: expense: %s user: %s share: %s%%>' % (self.expenditure,
  80                                                               self.user,
  81                                                               self.share)
  82
  83 class Subitem(object):
  84     def __repr__(self):
  85         return '<Subitem: expense: %s user: %s cost: %s>' % (self.expense,
  86                                                              self.user,
  87                                                              self.amount)
  88
  89 class Transfer(object):
  90     def __repr__(self):
  91         return '<Transfer: from %s to %s for %s>' % (self.debtor,
  92                                                      self.creditor,
  93                                                      self.amount)
  94
  95 ### DB/Class Mapping ###
  96
  97 orm.mapper(User, users)
  98
  99 orm.mapper(Expenditure, expenditures, properties={
 100         'spender': orm.relation(User, backref='expenditures')
 101 })
 102
 103 orm.mapper(Split, splits, properties={
 104         'expenditure': orm.relation(Expenditure, backref='splits'),
 105         'user': orm.relation(User)
 106 })
 107
 108 orm.mapper(Subitem, subitems, properties={
 109         'expenditure': orm.relation(Expenditure, backref='subitems'),
 110         'user': orm.relation(User)
 111 })
 112
 113 orm.mapper(Transfer, transfers, properties={
 114         'debtor': orm.relation(User,
 115                                primaryjoin=(transfers.c.debtor_id==\
 116                                                 users.c.id)),
 117         'creditor': orm.relation(User,
 118                                  primaryjoin=(transfers.c.creditor_id==\
 119                                                   users.c.id))
 120 })
 121
 122 __all__ = [users, expenditures, splits, subitems, transfers,
 123            User, Expenditure, Split, Subitem, Transfer,
 124            meta]