sqlalchemy lookup tables

Question

Hi I have a table in 3NF form

ftype_table = Table(
    \'FTYPE\',
    Column(\'ftypeid\', Integer, primary_key=True),
    Column(\'typename\', String(50)),
          


        

Answer 1

Since declarative_base and zzzeek code does not work with sqlalchemy 0.4, I used the following cache so that new objects also stay unique if they are not present in the db

class FileTypeCache(dict):
    def __missing__(self, key):
        try:
          obj = self[key] = Session.query(FileType).filter_by(typename=key).one()
          return obj
        except InvalidRequestError:
          return obj=self[key]= FileType(key)
          return obj

override eq of FileType

class FileType(object):
    def __init__(self, typename)
       self.typename=typename
    def __eq__(self):
        if isinstance(other, FileType):
            return self.typename == other.typename
        else:
            return False