begin adding class resources for session 2

Author: cewing

resources/session02/ljshell.py

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+from pyramid.paster import get_appsettings, setup_logging
+from sqlalchemy import engine_from_config
+from sqlalchemy.orm import sessionmaker
+
+config_uri = 'development.ini'
+setup_logging(config_uri)
+settings = get_appsettings(config_uri)
+engine = engine_from_config(settings, 'sqlalchemy.')
+Session = sessionmaker(bind=engine)

resources/session02/models.py

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+import datetime
+from sqlalchemy import (
+    Column,
+    DateTime,
+    Index,
+    Integer,
+    Text,
+    Unicode,
+    UnicodeText,
+    )
+
+import sqlalchemy as sa
+from sqlalchemy.ext.declarative import declarative_base
+
+from sqlalchemy.orm import (
+    scoped_session,
+    sessionmaker,
+    )
+
+from zope.sqlalchemy import ZopeTransactionExtension
+
+DBSession = scoped_session(sessionmaker(extension=ZopeTransactionExtension()))
+Base = declarative_base()
+
+
+class MyModel(Base):
+    __tablename__ = 'models'
+    id = Column(Integer, primary_key=True)
+    name = Column(Text)
+    value = Column(Integer)
+
+Index('my_index', MyModel.name, unique=True, mysql_length=255)
+
+
+class Entry(Base):
+    __tablename__ = 'entries'
+    id = Column(Integer, primary_key=True)
+    title = Column(Unicode(255), unique=True, nullable=False)
+    body = Column(UnicodeText, default=u'')
+    created = Column(DateTime, default=datetime.datetime.utcnow)
+    edited = Column(DateTime, default=datetime.datetime.utcnow)
+
+    @classmethod
+    def all(cls):
+        """return a query with all entries, ordered by creation date reversed
+        """
+        return DBSession.query(cls).order_by(sa.desc(cls.created)).all()
+
+    @classmethod
+    def by_id(cls, id):
+        """return a single entry identified by id
+
+        If no entry exists with the provided id, return None
+        """
+        return DBSession.query(cls).get(id)