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

Just create a cache of FileType objects, so that the database lookup occurs only the first time you use a given file type:

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

filetype_cache = FileTypeCache()

file=File()
file.size=10
file.filetype= filetype_cache['PPT']

should work, modulo typos.