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.user import User
   6 from bluechips.model.expenditure import Expenditure
   7 from bluechips.model.split import Split
   8 from bluechips.model.subitem import Subitem
   9 from bluechips.model.transfer import Transfer
  10
  11 from bluechips.model import meta
  12 from bluechips.model import types
  13
  14 from datetime import datetime
  15
  16 def init_model(engine):
  17     """Call me before using any of the tables or classes in the model"""
  18
  19     sm = orm.sessionmaker(autoflush=True, transactional=True, bind=engine)
  20
  21     meta.engine = engine
  22     meta.Session = orm.scoped_session(sm)
  23
  24 ### Database Schemas ###
  25
  26 users = sa.Table('users', meta.metadata,
  27                  sa.Column('id', sa.types.Integer, primary_key=True),
  28                  sa.Column('username', sa.types.Unicode(32), nullable=False),
  29                  sa.Column('name', sa.types.Unicode(64)),
  30                  sa.Column('resident', sa.types.Boolean, default=True)
  31                  )
  32
  33 expenditures = sa.Table('expenditures', meta.metadata,
  34                         sa.Column('id', sa.types.Integer, primary_key=True),
  35                         sa.Column('spender_id', sa.types.Integer,
  36                                   sa.ForeignKey('users.id'), nullable=False),
  37                         sa.Column('amount', types.DBCurrency, nullable=False),
  38                         sa.Column('description', sa.types.Text),
  39                         sa.Column('date', sa.types.Date, default=datetime.now),
  40                         sa.Column('entered_time', sa.types.DateTime,
  41                                   default=datetime.utcnow)
  42                         )
  43
  44 splits = sa.Table('splits', 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('share', types.DBCurrency, nullable=False)
  51                   )
  52
  53 subitems = sa.Table('subitems', meta.metadata,
  54                     sa.Column('id', sa.types.Integer, primary_key=True),
  55                     sa.Column('expenditure_id', sa.types.Integer,
  56                               sa.ForeignKey('expenditures.id'), nullable=False),
  57                     sa.Column('user_id', sa.types.Integer,
  58                               sa.ForeignKey('users.id'), nullable=False),
  59                     sa.Column('amount', types.DBCurrency, nullable=False)
  60                     )
  61
  62 transfers = sa.Table('transfers', meta.metadata,
  63                      sa.Column('id', sa.types.Integer, primary_key=True),
  64                      sa.Column('debtor_id', sa.types.Integer,
  65                                sa.ForeignKey('users.id'), nullable=False),
  66                      sa.Column('creditor_id', sa.types.Integer,
  67                                sa.ForeignKey('users.id'), nullable=False),
  68                      sa.Column('amount', types.DBCurrency, nullable=False),
  69                      sa.Column('description', sa.Text, default=None),
  70                      sa.Column('date', sa.types.Date, default=datetime.now),
  71                      sa.Column('entered_time', sa.types.DateTime,
  72                                default=datetime.utcnow)
  73                      )
  74
  75 ### DB/Class Mapping ###
  76
  77 orm.mapper(User, users,
  78            properties={
  79         'expenditures': orm.relation(Expenditure,
  80                                      backref='spender')
  81 })
  82
  83 orm.mapper(Expenditure, expenditures,
  84            order_by=[expenditures.c.date.desc(), expenditures.c.entered_time.desc()],
  85            properties={
  86         'splits': orm.relation(Split, backref='expenditure',
  87                                cascade='all, delete'),
  88         'subitems': orm.relation(Subitem, backref='expenditure',
  89                                  cascade='all, delete')
  90 })
  91
  92 orm.mapper(Split, splits, properties={
  93         'user': orm.relation(User)
  94 })
  95
  96 orm.mapper(Subitem, subitems, properties={
  97         'user': orm.relation(User)
  98 })
  99
 100 orm.mapper(Transfer, transfers,
 101            order_by=[transfers.c.date.desc(), transfers.c.entered_time.desc()],
 102            properties={
 103         'debtor': orm.relation(User,
 104                                primaryjoin=(transfers.c.debtor_id==\
 105                                                 users.c.id)),
 106         'creditor': orm.relation(User,
 107                                  primaryjoin=(transfers.c.creditor_id==\
 108                                                   users.c.id))
 109 })
 110
 111 __all__ = ['users', 'expenditures', 'splits', 'subitems', 'transfers',
 112            'User', 'Expenditure', 'Split', 'Subitem', 'Transfer',
 113            'meta']