Hi Michael,
Thanks for your reply.
First an apology, my program is now working.... It was a silly mistake...
Second, I agree that what I am doing is not the most elegant thing I've ever
done...
.to put it mildly... Yet, in most cases, the "fixRace" function will only be
run once at startup .....
In all but one case you only deal with one race. So that's not as bad as it
sounds...
Still the application that input data into the database does need to deal with
multiple races.
In that case I only keep one secondary mapper attached to the class and only
create a new
one when needed (i.e. when the race changes) (I probably need to "delete" the
old mapper if present)
At the bottom you will see the actual definition/mapping I use.
I guess that I may be able to map the various attributes of dbPeople and dbRace
to attributes of dbRaceParticipant
and deal with that object when needed, but I still see no elegant way of
"fixing" the race, either I
create a secondary mapper (same as now essentially) or I need to pass the race
as an argument
to all my queries... which is exactly what I am trying to avoid.
Cheers,
François
Here is an excerpt of my definitions.... draft in progress
=========+%<================%<================
tblPeople=Table("People",
Column("id", Integer, primary_key = True),
Column("Nickname",Unicode(32),nullable=False,index=True),
Column("Firstname",Unicode(32),nullable=False),
Column("Lastname",Unicode(32),nullable=False,index=True),
Column("Email",VARCHAR(64),index=True),
Column("Birthdate",Date),
Column("Gender",Enum(["Male","Female"]),nullable=False),
Column("Nationality",Country,nullable=False),
Column("Address",Unicode(256)),
Column("Zip",Unicode(32)),
Column("Country",Country),
Column("Tel",String(16)),
Column("Tel_Ext",String(4)),
Column("Mobile",String(16)),
Column("Picture_id",Integer,ForeignKey("ADM_Files.id"), nullable=True),
Column("Tag",String(32)),
Column("Active",Boolean,default=True))
tbbPeopleidx=Index('OnlyOne', tblPeople.c.Nickname,tblPeople.c.Firstname,
tblPeople.c.Lastname, unique=True)
class dbPeople(object):
def __str__(self):
return self.Fullname()
def Fullname(self):
return unicode(self.Firstname)+u" "+unicode(self.Lastname)
def age(self,adate=None):
"""Compute the age of a person. If adate is set the age is computed
at the given date"""
if adate is None:
adate=datetime.date.today()
myage=adate.year-self.Birthdate.year
if adate.month<self.Birthdate.month:
myage -=1
elif adate.month==self.Birthdate.month:
if adate.day<self.Birthdate.day:
myage -=1
return myage
# Mapping a Racer with a Race
tblRaceParticipant=Table("Race_Participant",
Column("id", Integer, primary_key = True),
Column("Race_id",Integer,ForeignKey("Race.id"), nullable=False),
Column("Racer_id",Integer,ForeignKey('People.id'), nullable=False),
Column("Team_id",Integer,ForeignKey('Team.id'), nullable=True),
Column("Weight",DECIMAL(4,1), nullable=True),
Column("Age",Integer, nullable=True),
Column("Height",Integer, nullable=True),
#Column("Categories",String, nullable=True),
Column("isActive",Boolean, nullable=False,default=True),
Column("Retired",TIMESTAMP, nullable=True),
Column("Comment",Unicode))
tbbParticipantidx=Index('OnlyOne',
tblRaceParticipant.c.Race_id,tblRaceParticipant.c.Racer_id, unique=True)
class dbRaceParticipant(object):
def __str__(self):
return str(self.Racer)+u" during "+str(self.Race)
#Defining races
tblRace=Table("Race",
Column("id", Integer, primary_key = True),
Column("Name",Unicode(64),nullable=False),
Column("Type",Enum(["Team","Individual"]),nullable=False),
Column("Vehicle",Enum(["None","One","Multiple","Individual"]),nullable=False,default="One"),
Column("Organiser_id",Integer,ForeignKey('People.id'),nullable=True),
Column("Description",Unicode),
Column("Logo_id",Integer,ForeignKey("ADM_Files.id"), nullable=True),
Column("Standing",Unicode(32)))
class dbRace(object):
def __str__(self):
return self.Name
def getRegistrationRecord(self,people):
"""There must be a session here"""
for rec in self.Registration:
if rec.Racer==people:
return rec
#
dbRaceParticipant.mapper=mapper(dbRaceParticipant, tblRaceParticipant,
properties = {
'Races' : relation(dbRace, backref=backref('Registration')),
'Racer' : relation(dbPeople, backref=backref('Registration')),
"Team":relation(dbTeam )})
# Organiser with back reference
dbRace.mapper=mapper(dbRace, tblRace,
properties = {
'Organiser' : relation(dbPeople, backref=backref('Organise')),
"Racers":relation(dbPeople,secondary=tblRaceParticipant,
primaryjoin=tblRace.c.id==tblRaceParticipant.c.Race_id,
secondaryjoin=tblPeople.c.id==tblRaceParticipant.c.Racer_id),
"Teams":relation(dbTeam,secondary=tblRaceParticipant,
primaryjoin=tblRace.c.id==tblRaceParticipant.c.Race_id,
secondaryjoin=tblTeam.c.id==tblRaceParticipant.c.Team_id),
"Logo":relation(dbFile)})
# Picture is mapped to the corresponding file.
#We have a list of participation record
dbPeople.mapper=mapper(dbPeople, tblPeople, properties = {'Picture' :
relation(dbFile, cascade="all")})
def fixRace(obj,race):
"""Create a secondary mapper where the race is fixed
This has nothing to do with "fixing races", This limits the
dataset to those records directly related to the race at hand
"""
if isinstance(race,int):
myraceid=race
else:
myraceid=race.id
try:
test=obj.fixedRaceId != myraceid
except:
test=True
if test:
if obj==dbPeople:
s=tblPeople.select(and_(tblRaceParticipant.c.Race_id==myraceid,tblPeople.c.id==tblRaceParticipant.c.Racer_id)).alias("per_race_select")
dbPeople.inRace=mapper(dbPeople,s,non_primary=True)
=========+%<================%<================
> Michael Bayer wrote:
> if you are creating mappers within functions on a per-request basis,
> that is a Very Bad Idea. dont create ad-hoc mappers just to create
> queries. you should only have one mapper per class, corresponding to
> the scope of the class itself. i am beginning to consider if the
> "non_primary" keyword argument to mapper can even be deprecated since i
> am hypothesizing that it doesn't provide any unique functionality, and
> only leads to problems.
>
> if you want a particualr query to occur, you should create the query
> you want yourself. without seeing anything that you are doing, if you
> are having issues, things like that would be the biggest reason.
>
>
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