Hi
I am able to create the field through in postgres.
When i execute that sql statement :-
CREATE TABLE "visit_visit_research" (
"id" serial NOT NULL PRIMARY KEY,
"visit_id" integer NOT NULL REFERENCES "visit_visit" ("id") DEFERRABLE
INITIALLY DEFERRED,
"research_id" integer NOT NULL REFERENCES "www_researchprotocol" ("id")
DEFERRABLE INITIALLY DEFERRED,
UNIQUE ("visit_id", "research_id")
)
;
I get this :-
psql:db/2012-03-24_research_protocol.sql:7: NOTICE: CREATE TABLE will
create implicit sequence "visit_visit_research_id_seq" for serial column "
visit_visit_research.id"
psql:db/2012-03-24_research_protocol.sql:7: NOTICE: CREATE TABLE / PRIMARY
KEY will create implicit index "visit_visit_research_pkey" for table
"visit_visit_research"
psql:db/2012-03-24_research_protocol.sql:7: NOTICE: CREATE TABLE / UNIQUE
will create implicit index "visit_visit_research_visit_id_key" for table
"visit_visit_research"
CREATE TABLE
So the field gets created but when i am going in django-admin in table
visit i am getting an error.It is not showing up two boxes i mean the many
to many widget which django displays.
This is the error
Exception Type: DatabaseError at /admin/visit/visit/20/
Exception Value: column visit_visit_research.researchprotocol_id does not
exist
LINE 1: ...visit_research" ON ("www_researchprotocol"."id" = "visit_vis...
^
Any help will be appreciated.
Thanks in advance.
On Thu, Mar 22, 2012 at 6:26 PM, Joel Goldstick <joel.goldst...@gmail.com>wrote:
> On Thu, Mar 22, 2012 at 6:55 AM, Nikhil Verma <varma.nikhi...@gmail.com>
> wrote:
> > Hi All
> >
> > I want to add a ManyToManyField to an existing django model.
> >
> > I can use sql app_name and see the statement.
> >
> > My models
> >
> > Class Visit(modes.Model):
> > x = something
> > . ......
> > ...... and so on
> > # finally Here i want to add that field research protol
> > research_protocol =
> > models.ManyToManyField(ResearchProtocol,blank=True)
> >
> >
> >
> > class ResearchProtocol(models.Model):
> > title = models.CharField(max_length=30)
> > description = models.TextField()
> > start_date = models.DateField(_("Date Started"))
> > end_date = models.DateField(_("Date Completed"))
> >
> > def __unicode__(self):
> > return '%s' % self.title
> >
> >
> >
> > So i made an sql statement like this:-
> >
> > CREATE TABLE "visit_visit_research_protocols"
> > (
> > "id" integer NOT NULL PRIMARY KEY,
> >
> > "visit_id" integer NOT NULL REFERENCES "visit_visit" ("id")
> DEFERRABLE
> > INITIALLY DEFERRED,
> > "research_protocols_id" varchar(80) NOT NULL REFERENCES
> > "www_researchprotocol" ("title") DEFERRABLE INITIALLY DEFERRED,
> > UNIQUE ("visit_id","research_protocols_id")
> > );
> >
> > The dbshell says:-
> > psql:db/2012-03-22_research_id.sql:8: NOTICE: CREATE TABLE / PRIMARY KEY
> > will create implicit index "visit_visit_research_protocols_pkey" for
> table
> > "visit_visit_research_protocols"
> > psql:db/2012-03-22_research_id.sql:8: NOTICE: CREATE TABLE / UNIQUE will
> > create implicit index
> > "visit_visit_research_protocol_visit_id_research_protocols_i_key" for
> table
> > "visit_visit_research_protocols"
> > psql:db/2012-03-22_research_id.sql:8: ERROR: there is no unique
> constraint
> > matching given keys for referenced table "www_researchprotocol"
> >
> >
> >
> > What mistake i am doing ?
> >
> > Thanks in advance.
> >
> >
> > --
> > Regards
> > Nikhil Verma
> > +91-958-273-3156
> >
> > --
> > You received this message because you are subscribed to the Google Groups
> > "Django users" group.
> > To post to this group, send email to django-users@googlegroups.com.
> > To unsubscribe from this group, send email to
> > django-users+unsubscr...@googlegroups.com.
> > For more options, visit this group at
> > http://groups.google.com/group/django-users?hl=en.
>
> You can't add the many to many relationship after you already have the
> model with django. See this:
>
> http://stackoverflow.com/questions/830130/adding-a-field-to-an-existing-django-model
> That answer points to South, which I have played with but am not
> proficient yet. Another thought is to create a new model, identical
> to your present one, but include the many2many and dbsync that. If it
> works, copy your data from your old model into your new model.
>
>
> --
> Joel Goldstick
>
> --
> You received this message because you are subscribed to the Google Groups
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> To post to this group, send email to django-users@googlegroups.com.
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>
>
--
Regards
Nikhil Verma
+91-958-273-3156
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