From a5039375dfdaa2c1dd5bf753ac5511b615f99515 Mon Sep 17 00:00:00 2001
From: Evan Broder <broder@mit.edu>
Date: Sun, 13 Jul 2008 02:47:54 +0000
Subject: [PATCH] Define the model

---
 bluechips/model/__init__.py | 123 ++++++++++++++++++++++++++++++------
 bluechips/model/types.py    |  22 +++++++
 2 files changed, 127 insertions(+), 18 deletions(-)
 create mode 100644 bluechips/model/types.py

diff --git a/bluechips/model/__init__.py b/bluechips/model/__init__.py
index d64463b..26686ff 100644
--- a/bluechips/model/__init__.py
+++ b/bluechips/model/__init__.py
@@ -3,6 +3,7 @@ import sqlalchemy as sa
 from sqlalchemy import orm
 
 from bluechips.model import meta
+from bluechips.model import types
 
 def init_model(engine):
     """Call me before using any of the tables or classes in the model"""
@@ -17,22 +18,108 @@ def init_model(engine):
     meta.engine = engine
     meta.Session = orm.scoped_session(sm)
 
+### Database Schemas ###
 
-## Non-reflected tables may be defined and mapped at module level
-#foo_table = sa.Table("Foo", meta.metadata,
-#    sa.Column("id", sa.types.Integer, primary_key=True),
-#    sa.Column("bar", sa.types.String(255), nullable=False),
-#    )
-#
-#class Foo(object):
-#    pass
-#
-#orm.mapper(Foo, foo_table)
-
-
-## Classes for reflected tables may be defined here, but the table and
-## mapping itself must be done in the init_model function
-#reflected_table = None
-#
-#class Reflected(object):
-#    pass
+users = sa.Table('users', meta.metadata,
+                 sa.Column('id', sa.types.Integer, primary_key=True),
+                 sa.Column('username', sa.types.Unicode(32), nullable=False),
+                 sa.Column('name', sa.types.Unicode(64)),
+                 sa.Column('resident', sa.types.Boolean, default=True)
+                 )
+
+expenditures = sa.Table('expenditures', meta.metadata,
+                        sa.Column('id', sa.types.Integer, primary_key=True),
+                        sa.Column('spender_id', sa.types.Integer,
+                                  sa.ForeignKey('users.id'), nullable=False),
+                        sa.Column('amount', types.Currency, nullable=False),
+                        sa.Column('date', sa.types.Date, default=sa.func.now),
+                        sa.Column('entered_time', sa.types.DateTime, 
+                                  default=sa.func.now)
+                        )
+
+splits = sa.Table('splits', meta.metadata,
+                  sa.Column('id', sa.types.Integer, primary_key=True),
+                  sa.Column('expenditure_id', sa.types.Integer,
+                            sa.ForeignKey('expenditures.id'), nullable=False),
+                  sa.Column('user_id', sa.types.Integer,
+                            sa.ForeignKey('users.id'), nullable=False),
+                  sa.Column('share', sa.types.Integer, nullable=False)
+                  )
+
+subitems = sa.Table('subitems', meta.metadata,
+                    sa.Column('id', sa.types.Integer, primary_key=True),
+                    sa.Column('expenditure_id', sa.types.Integer,
+                              sa.ForeignKey('expenditures.id'), nullable=False),
+                    sa.Column('user_id', sa.types.Integer,
+                              sa.ForeignKey('users.id'), nullable=False),
+                    sa.Column('amount', types.Currency, nullable=False)
+                    )
+
+transfers = sa.Table('transfers', meta.metadata,
+                     sa.Column('id', sa.types.Integer, primary_key=True),
+                     sa.Column('debtor_id', sa.types.Integer,
+                               sa.ForeignKey('users.id'), nullable=False),
+                     sa.Column('creditor_id', sa.types.Integer,
+                               sa.ForeignKey('users.id'), nullable=False),
+                     sa.Column('amount', types.Currency, nullable=False),
+                     sa.Column('date', sa.types.Date, default=sa.func.now),
+                     sa.Column('entered_time', sa.types.DateTime,
+                               default=sa.func.now),
+                     sa.Column('desc', sa.Text, default=None)
+                     )
+
+### ORM Classes ###
+
+class User(object):
+    def __repr__(self):
+        return '<User: %w>' % (self.username)
+
+class Expenditure(object):
+    def __repr__(self):
+        return '<Expenditure: spender: %s spent: %s>' % (self.spender,
+                                               self.amount)
+
+class Split(object):
+    def __repr__(self):
+        return '<Split: expense: %s user: %s share: %s%%>' % (self.expenditure,
+                                                              self.user,
+                                                              self.share)
+
+class Subitem(object):
+    def __repr__(self):
+        return '<Subitem: expense: %s user: %s cost: %s>' % (self.expense,
+                                                             self.user,
+                                                             self.amount)
+
+class Transfer(object):
+    def __repr__(self):
+        return '<Transfer: from %s to %s for %s>' % (self.debtor,
+                                                     self.creditor,
+                                                     self.amount)
+
+### DB/Class Mapping ###
+
+orm.mapper(User, users)
+
+orm.mapper(Expenditure, expenditures, properties={
+        'spender': orm.relation(User, backref='expenditures')
+})
+
+orm.mapper(Split, splits, properties={
+        'expenditure': orm.relation(Expenditure, backref='splits'),
+        'user': orm.relation(User)
+})
+
+orm.mapper(Subitem, subitems, properties={
+        'expenditure': orm.relation(Expenditure, backref='subitems'),
+        'user': orm.relation(User)
+})
+
+orm.mapper(Transfer, transfers, properties={
+        'debtor': orm.relation(User),
+        'creditor': orm.relation(User)
+})
+
+__all__ = [users, expenditures, splits, subitems, transfers,
+           User, Expenditure, Split, Subitem, Transfer,
+           meta]
diff --git a/bluechips/model/types.py b/bluechips/model/types.py
new file mode 100644
index 0000000..1504d21
--- /dev/null
+++ b/bluechips/model/types.py
@@ -0,0 +1,22 @@
+"""
+Define special types used in BlueChips
+"""
+
+import sqlalchemy as sa
+from decimal import Decimal
+import locale
+
+class Currency(sa.types.TypeDecorator):
+    """
+    A type which represents monetary amounts internally as integers.
+    
+    This avoids binary/decimal float conversion issues
+    """
+    
+    impl = sa.types.Integer
+    
+    def process_bind_param(self, value, engine):
+        return int(value * 100)
+    
+    def convert_result_value(self, value, engine):
+        return Decimal(Decimal(value) / 100).quantize(Decimal("0.01"))
-- 
2.45.2