Hi Brian,
It seems like you don't really have an Many To Many relationship between
your "Song" and "Played" objects. I can see how you would have multiple
plays for one song, but considering that the Played model has a track_id,
would you ever have multiple songs for a single Play? It appears that
"track_id" is intended to be a foreign key into the Song table, so maybe
you could consider using a ForeignKey field to refer to your Song through
your Played object. Django will automatically create 2-way references so
you can get to your played objects from your song object::
class Played(models.Model):
played_id = models.IntegerField(primary_key=True)
track = models.ForeignKey('Song')
date_played = models.DateTimeField()
played_by = models.CharField(max_length=255L)
played_by_me = models.IntegerField()
class Meta:
db_table = 'played'
class Song(models.Model):
id = models.IntegerField(primary_key=True)
title = models.CharField(max_length=255L, blank=True)
class Meta:
db_table = 'song'
Then, you should be able to get all of the Plays for a particular song::
s = Song.objects.get(id=1229)
s.title # should be OK still
s.played_set.all() # should be a list of plays.
On Saturday, May 11, 2013 5:33:46 PM UTC-5, Brian Millham wrote:
>
> Hi all,
> I'm just trying to learn Django. I have an existing site that I wrote in
> PHP, and I'l considering converting it to Django,
>
> I have a legacy database that I don't want to make any changes to. I have
> the basics working in Django, but am having a problem with a
> ManyToManyField.
>
> Here are the 2 tables (simplified)
>
> class Played(models.Model):
> played_id = models.IntegerField(primary_key=True)
> track_id = models.IntegerField()
> date_played = models.DateTimeField()
> played_by = models.CharField(max_length=255L)
> played_by_me = models.IntegerField()
> class Meta:
> db_table = 'played'
>
> class Song(models.Model):
> id = models.IntegerField(primary_key=True)
> title = models.CharField(max_length=255L, blank=True)
> #These are what I've tried for ManyToMany with the error
> played = models.ManyToManyField(Played, db_column='id') # DatabaseError:
> (1146, "Table 'ampache.song_played' doesn't exist")
> played = models.ManyToManyField(Played, db_column='track_id') #
> DatabaseError: (1146, "Table 'ampache.song_played' doesn't exist")
> played = models.ManyToManyField(Played, db_table = 'played',
> db_column='id') # DatabaseError: (1054, "Unknown column 'T2.song_id' in
> 'where clause'")
> played = models.ManyToManyField(Played, db_table = 'played',
> db_column='track_id') # DatabaseError: (1054, "Unknown column 'T2.song_id'
> in 'where clause'")
> played = models.ManyToManyField(Played, through = 'played',
> db_column='id') # AttributeError: 'ManyToManyField' object has no attribute
> '_m2m_reverse_name_cache'
> class Meta:
> db_table = 'song'
>
> The code to produce the errors:
>
>> from djmusic.models import Song, Played
>> s = Song.objects.get(id=1229)
>> print s.title # Prints the title correctly
>> print s.played.all() # Generates one of the above errors
>>
>
> I know it's gotta be something simple I'm missing here. If I can get this
> figured out, there's a good chance that I'll convert my old PHP based site
> to Django.
>
> Thanks all!
>
>
>
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