Class Field

object --+    
         |    
Expression --+
             |
            Field

an instance of this class represents a database field

   a = Field(name, 'string', length=32, default=None, required=False,
       requires=IS_NOT_EMPTY(), ondelete='CASCADE',
       notnull=False, unique=False,
       uploadfield=True, widget=None, label=None, comment=None,
       uploadfield=True, # True means store on disk,
                         # 'a_field_name' means store in this field in db
                         # False means file content will be discarded.
       writable=True, readable=True, update=None, authorize=None,
       autodelete=False, represent=None, uploadfolder=None,
       uploadseparate=False # upload to separate directories by uuid_keys
                            # first 2 character and tablename.fieldname
                            # False - old behavior
                            # True - put uploaded file in
                            #   <uploaddir>/<tablename>.<fieldname>/uuid_key[:2]
                            #        directory)

to be used as argument of DAL.define_table

allowed field types: string, boolean, integer, double, text, blob, date, time, datetime, upload, password