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 from datetime import datetime
   9
  10 def init_model(engine):
  11     """Call me before using any of the tables or classes in the model"""
  12
  13     sm = orm.sessionmaker(autoflush=True, transactional=True, bind=engine)
  14
  15     meta.engine = engine
  16     meta.Session = orm.scoped_session(sm)
  17
  18 ### Database Schemas ###
  19
  20 users = sa.Table('users', meta.metadata,
  21                  sa.Column('id', sa.types.Integer, primary_key=True),
  22                  sa.Column('username', sa.types.Unicode(32), nullable=False),
  23                  sa.Column('name', sa.types.Unicode(64)),
  24                  sa.Column('resident', sa.types.Boolean, default=True)
  25                  )
  26
  27 expenditures = sa.Table('expenditures', meta.metadata,
  28                         sa.Column('id', sa.types.Integer, primary_key=True),
  29                         sa.Column('spender_id', sa.types.Integer,
  30                                   sa.ForeignKey('users.id'), nullable=False),
  31                         sa.Column('amount', types.Currency, nullable=False),
  32                         sa.Column('description', sa.types.Text),
  33                         sa.Column('date', sa.types.Date, default=datetime.now),
  34                         sa.Column('entered_time', sa.types.DateTime,
  35                                   default=datetime.now)
  36                         )
  37
  38 splits = sa.Table('splits', meta.metadata,
  39                   sa.Column('id', sa.types.Integer, primary_key=True),
  40                   sa.Column('expenditure_id', sa.types.Integer,
  41                             sa.ForeignKey('expenditures.id'), nullable=False),
  42                   sa.Column('user_id', sa.types.Integer,
  43                             sa.ForeignKey('users.id'), nullable=False),
  44                   sa.Column('share', types.Currency, nullable=False)
  45                   )
  46
  47 subitems = sa.Table('subitems', meta.metadata,
  48                     sa.Column('id', sa.types.Integer, primary_key=True),
  49                     sa.Column('expenditure_id', sa.types.Integer,
  50                               sa.ForeignKey('expenditures.id'), nullable=False),
  51                     sa.Column('user_id', sa.types.Integer,
  52                               sa.ForeignKey('users.id'), nullable=False),
  53                     sa.Column('amount', types.Currency, nullable=False)
  54                     )
  55
  56 transfers = sa.Table('transfers', meta.metadata,
  57                      sa.Column('id', sa.types.Integer, primary_key=True),
  58                      sa.Column('debtor_id', sa.types.Integer,
  59                                sa.ForeignKey('users.id'), nullable=False),
  60                      sa.Column('creditor_id', sa.types.Integer,
  61                                sa.ForeignKey('users.id'), nullable=False),
  62                      sa.Column('amount', types.Currency, nullable=False),
  63                      sa.Column('description', sa.Text, default=None),
  64                      sa.Column('date', sa.types.Date, default=datetime.now),
  65                      sa.Column('entered_time', sa.types.DateTime,
  66                                default=datetime.now)
  67                      )
  68
  69 ### ORM Classes ###
  70
  71 class User(object):
  72     def __repr__(self):
  73         return '<User: %s>' % (self.username)
  74
  75 class Expenditure(object):
  76     def __repr__(self):
  77         return '<Expenditure: spender: %s spent: %s>' % (self.spender,
  78                                                          self.amount)
  79
  80 class Split(object):
  81     def __repr__(self):
  82         return '<Split: expense: %s user: %s share: %s>' % (self.expenditure,
  83                                                             self.user,
  84                                                             self.share)
  85
  86 class Subitem(object):
  87     def __repr__(self):
  88         return '<Subitem: expense: %s user: %s cost: %s>' % (self.expense,
  89                                                              self.user,
  90                                                              self.amount)
  91
  92 class Transfer(object):
  93     def __repr__(self):
  94         return '<Transfer: from %s to %s for %s>' % (self.debtor,
  95                                                      self.creditor,
  96                                                      self.amount)
  97
  98 ### DB/Class Mapping ###
  99
 100 orm.mapper(User, users)
 101
 102 orm.mapper(Expenditure, expenditures, order_by=expenditures.c.date.desc(),
 103            properties={
 104         'spender': orm.relation(User,
 105                                 backref='expenditures',
 106                                 lazy=False)
 107 })
 108
 109 orm.mapper(Split, splits, properties={
 110         'expenditure': orm.relation(Expenditure, backref='splits'),
 111         'user': orm.relation(User)
 112 })
 113
 114 orm.mapper(Subitem, subitems, properties={
 115         'expenditure': orm.relation(Expenditure, backref='subitems'),
 116         'user': orm.relation(User)
 117 })
 118
 119 orm.mapper(Transfer, transfers, order_by=transfers.c.date.desc(),
 120            properties={
 121         'debtor': orm.relation(User,
 122                                primaryjoin=(transfers.c.debtor_id==\
 123                                                 users.c.id),
 124                                lazy=False),
 125         'creditor': orm.relation(User,
 126                                  primaryjoin=(transfers.c.creditor_id==\
 127                                                   users.c.id),
 128                                  lazy=False)
 129 })
 130
 131 __all__ = ['users', 'expenditures', 'splits', 'subitems', 'transfers',
 132            'User', 'Expenditure', 'Split', 'Subitem', 'Transfer',
 133            'meta']