Why is the error appearing in django/admin? Migrations ok, I need to have 3 items in the table where I will have results.
class Robot(models.Model):
"""Robot model, speed and position simulation"""
product = models.IntegerField(choices=CHOOSE)
velocity = models.FloatField()
positionX = models.FloatField()
positionY = models.FloatField()
angleTHETA = models.FloatField()
class Meta:`enter code here`
verbose_name = "Robot"
verbose_name_plural = "Robots"
def __str__(self):
resum = self.get_product_display()
return resum
ProgrammingError at /admin/robot/robot/
column robot_robot.velocity does not exist
LINE 1: ...LECT "robot_robot"."id", "robot_robot"."product", "robot_rob...
====
Hello, can someone help me with the above problem, I keep getting this error:
django.db.utils.ProgrammingError: relation "robot_cleanrobot" does not exist
LINE 1: SELECT COUNT(*) AS "__count" FROM "robot_cleanrobot"
first migrations done
then pip install -r requirements.txt
python manage.py startapp
settings
makemigrations & migrate
add model
register a view
nothing helps me, I have done many times from scratch, even deleted the whole directory and also nothing,
I changed the model in the new project and nothing
At the beginning it worked ok for the first time, but when I added the float it all went down - I do not know what to do about it. Please help. Thx.
class CleanRobot(models.Model):
"""..."""
name = models.CharField(max_length=100, null=True, blank=True)
class Meta:
verbose_name = "CleanRobot"
verbose_name_plural = "CleanRobots"
def __str__(self):
return self.name
=================================
Ok, not working: ok step by step what i am doing:
i create a django project
enable (venv)
makemigrations
migrate
pip install -r requirements.txt
copy to settinigs_local project
python manage.py start app
change settings - add code -> reference to local + register application
add code to models
register models
makemigrations
migrate
runserver
dajngo/admin
... +Add is ok, by name entering I get error... I have other projects on my computer and they work normally... I have other projects on my computer and they work normally... not today I have deleted the whole folder for the 20th time...
You are getting the error because the database fields that you requested probably do not exist. Remember to run both makemigrations and migrate commands.
As #ElvinJafarov suggested, migrate the database before proceeding. You get the message about angleTHETA field because of constraints on the database - that’s completely normal. As stated in the message "This is because the database needs something to populate the existing rows".
At this point you can quit and manually define the default value in the models.py (press 2 in message prompt). After this change your Robot by setting a field default, so that Django can populate DB with the default value, e.g.:
angleTHETA = models.FloatField(default=0)
You can also change DB constraints by allowing it to have empty values.
angleTHETA = models.FloatField(null=True, blank=True)
In general, I advise you to read the documentation on migrations.
Update 1:
From your description it seems that first you ran makemigrations and migrate commands, and then created the model. It should be the other way around - first make the model, then run makemigrations. If it went well you should see something like this
and also you should have a new non-empty file in your app's migrations folder. Then run migrate command. You should see something like:
If something went wrong, post the message you did get.
Works:
I don't know which of these things worked but:
i had alpha name and alpha project name so i changed to alphaapp,
after migration 2 I created a new superuser
Maybe this will be useful for someone ;)
Related
I'm trying to update an old django app from 1.1.x to 1.8 LTS, which has involved updating paths, as I apps move apps around.
However, I'm unable to generate migrations for one app, and I can't see how to reference a namespaced app model correctly (assuming that's the problem)
If I've moved files from PROJECT/news/models to PROJECT/site_name/news/models, how should I be referencing these models in in foreign keys or ManyToManyFields?
My app
I have a projects app I want to make migrations for. Projects in some_org/projects, and listed in installed apps like so:
INSTALLED_APPS = (
'some_org.maps',
'some_org.library',
'some_org.extras',
'some_org.news',
'some_org.projects',
'some_org.members',
'some_org.comments',
)
All the apps with the namespace are within the some_org directory.
Here's an abridged view of the models file in the projects app:
# some_org/projects/models.py
from some_org.library import Paper
class Project(models.Model):
name = models.CharField(max_length=30)
def get_children(self):
return ProjectPage.objects.filter(level=1, publish=True, project=self)
def has_library(self):
return Paper.objects.filter(projects=self).count() > 0
Calling ./manage.py makemigrations library, gives me this error:
ValueError: Lookup failed for model referenced by field library.Paper.projects: projects.Project
When I look in the Paper model, it looks like this:
class Paper(models.Model):
# snip
# NewsLinkSubject, Projects et al used to in an app on
# the project root, like `./app_name/models.py`, but is now
# in `some_org/app_name/models.py`
subjects = models.ManyToManyField("news.NewsLinkSubject", blank=True)
projects = models.ManyToManyField("projects.Project", blank=True,)
country = models.ForeignKey("maps.Country", null=True, blank=True)
I initially wonder if the label for the app is wrong, and try the projects ManytoMany field to:
projects = models.ManyToManyField("some_org.projects.Project", blank=True,)
This gives a different error:
ERRORS:
library.Paper.subjects: (fields.E300) Field defines a relation with model some_org.projects.Project', which is either not installed, or is abstract.
As far as I can tell the app is installed, and the models aren't abstract.
I'm pretty stumped - what am I doing wrong, and how can I fix this so I can make migrations for these apps?
I'm using Django 1.8.17, and Python 2.7.13.
You should define an app_label in the Meta class for your models. Whatever you put in there becomes the first part of the name you use in the ManyToManyField definition.
I want to get the name of the last applied migration in Django. I know that Django migrations are stored in django_migrations table, however django.db.migrations.migration.Migration is not a models.Model backed by that table. This means you cannot do:
migration_info = Migration.objects.all()
Is there any built-in way of retrieveing the data from django_migrations, or should i just create my own read-only Model:
class MigrationInfo(models.Model):
class Meta:
managed = False
db_table = "django_migrations"
This works on Django 1.11/1.8/2.1 & 3.0.4:
from django.db.migrations.recorder import MigrationRecorder
last_migration = MigrationRecorder.Migration.objects.latest('id')
print(last_migration.app) # The app where the migration belongs
print(last_migration.name) # The name of the migration
There doesn't seem to be documentation for this command, but here you may find the source code which is documented properly.
To store information about applied migrations Django uses plain table and it is accessible as #classproperty through the MigrationRecorder class:
from django.db.migrations.recorder import MigrationRecorder
lm = MigrationRecorder.Migration.objects.filter(app='core').last()
It is also easy to retrieve this information from the command line:
Get the last applied migration for the particular app
python manage.py showmigrations --list <app_name> | grep "\[X\]" | tail -1
Get the ordered list of unapplied migrations
python manage.py showmigrations --plan | grep "\[ \]"
A lot easier, you could also parse out the last line of:
./manage.py showmigrations <app_name>
I've searched for the solution on internet and here and didn't find one. It seems like something needs to be changed or added, or maybe I just did something wrong.
I recently started a new project with Django and although I know a little bit of web programming and python I'm totally new to Django.
Everything was ok until I decided to add a new column to my MySQL DB. So, I with easy_install I installed Django Evolution in my VirtualEnv, then I added "django_evolution" in my INSTALLED_APPS.
After this, I ran 'python manage.py syncdb'
Then I added a new field (preview) in my Models file:
from django.db import models
# Create your models here.
class posts(models.Model):
author = models.CharField(max_length = 30)
title = models.CharField(max_length = 100)
bodytext = models.TextField()
preview = models.TextField()
timestamp = models.DateTimeField()
After this I ran 'python manage.py evolve --hint --execute' command.
In the terminal I got an error: ConnectionRouter' object has no attribute 'allow_syncdb'
When I'm trying to access the page I get: 1054, "Unknown column 'myblog_posts.preview' in 'field list'"
It seems like for some reason a preview column can't be added to the DB with Django Evolution.
What I'm doing wrong?
I'm doing a sqlite3 data migration using South. My old schema has the following model for UserProfile:
class UserProfile(models.Model):
user = models.OneToOneField(User)
weekOne = models.OneToOneField(WeekOne)
weekTwo = models.OneToOneField(WeekTwo)
weekThree = models.OneToOneField(WeekThree)
But I have sense added a number of new weeks, i.e., weekFour, weekFive, weekSix, etc. Every week is itself a model, inheriting from a generic Week model. So the basic prototype of a Week model looks like this:
class WeekOne(Week):
name = u'Week One'
exercises = ['squats', 'lunges', 'stairDaysCount', 'skipStairs']
# Required benchmarks for given exercises
squatBenchmark = 1000
lungeBenchmark = 250
stairDaysCountBenchmark = 3
totalGoals = 4
My question is, what kind of code should I put in my datamigration code so that I can populate old UserProfiles with the additional weeks. I had something like this in mind:
def forwards(self, orm):
for user in orm.UserProfile.objects.all():
user.weekFour = orm.WeekFour()
user.weekFive = orm.weekFive()
# etc.
But that doesn't seem to be working. I get this error when I try to run schema migration:
Migration 'my_app:0002_newWeeks' is marked for no-dry-run
And later this:
DatabaseError: no such column: my_app_userprofile.weekFour_id
Just run this in the terminal
python manage.py schemamigration myapp --auto
Then
python manage.py migrate
Following is my model:
class myUser_Group(models.Model):
name = models.CharField(max_length=100)
class Channel(models.Model):
name = models.CharField(max_length=100)
description = models.CharField(max_length=1000)
belongs_to_group = models.ManyToManyField(myUser_Group)
class Video(models.Model):
video_url = models.URLField(max_length=300)
belongs_to_channel = models.ManyToManyField(Channel)
description = models.CharField(max_length=1000)
tags = TagField()
class UserProfile(models.Model):
user = models.OneToOneField(User)
class User_History(models.Model):
date_time = models.DateTimeField()
user = models.ForeignKey(UserProfile, null=True, blank=True)
videos_watched = models.ManyToManyField(Video)
I just wanted to remove the underscores from all the class names so that User_History looks UserHistory, also the foreign keys should be updated. I tried using south but could not find it in the documentaion.
One way is export the data, uninstall south, delete migration, rename the table and then import data again. Is there any other way to do it?
You can do this using just South.
For this example I have an app called usergroups with the following model:
class myUser_Group(models.Model):
name = models.CharField(max_length=100)
which I assume is already under migration control with South.
Make the model name change:
class MyUserGroup(models.Model):
name = models.CharField(max_length=100)
and create an empty migration from south
$ python manage.py schemamigration usergroups model_name_change --empty
This will create a skeleton migration file for you to specify what happens. If we edit it so it looks like this (this file will be in the app_name/migrations/ folder -- usergroups/migrations/ in this case):
import datetime
from south.db import db
from south.v2 import SchemaMigration
from django.db import models
class Migration(SchemaMigration):
def forwards(self, orm):
# Change the table name from the old model name to the new model name
# ADD THIS LINE (using the correct table names)
db.rename_table('usergroups_myuser_group', 'usergroups_myusergroup')
def backwards(self, orm):
# Provide a way to do the migration backwards by renaming the other way
# ADD THIS LINE (using the correct table names)
db.rename_table('usergroups_myusergroup', 'usergroups_myuser_group')
models = {
'usergroups.myusergroup': {
'Meta': {'object_name': 'MyUserGroup'},
'id': ('django.db.models.fields.AutoField', [], {'primary_key': 'True'}),
'name': ('django.db.models.fields.CharField', [], {'max_length': '100'})
}
}
complete_apps = ['usergroups']
In the forwards method we are renaming the database table name to match what the django ORM will look for with the new model name. We reverse the change in backwards to ensure the migration can be stepped back if required.
Run the migration with no need to import/export the exisiting data:
$ python manage.py migrate
The only step remaining is to update the foreign key and many-to-many columns in the models that refer to myUser_Group and change to refer to MyUserGroup.
mmcnickle's solution may work and seems reasonable but I prefer a two step process. In the first step you change the table name.
In your model make sure you have your new table name in:
class Meta:
db_table = new_table_name'
Then like mmcnickle suggested, create a custom migration:
python manage.py schemamigration xyz migration_name --empty
You can read more about that here:
https://docs.djangoproject.com/en/dev/ref/models/options/
Now with your custom migration also add the line to rename your table forward and backwards:
db.rename_table("old_table_name","new_table_name")
This can be enough to migrate and change the table name but if you have been using the Class Meta custom table name before then you'll have to do a bit more. So I would say as a rule, just to be safe do a search in your migration file for "old_table_name" and change any entries you find to the new table name. For example, if you were previously using the Class Meta custom table name, you will likely see:
'Meta': {'object_name': 'ModelNameYouWillChangeNext', 'db_table': "u'old_table_name'"},
So you'll need to change that old table name to the new one.
Now you can migrate with:
python manage.py migrate xyz
At this point your app should run since all you have done is change the table name and tell Django to look for the new table name.
The second step is to change your model name. The difficulty of this really depends on your app but basically you just need to change all the code that references the old model name to code that references the new model name. You also probably need to change some file names and directory names if you have used your old model name in them for organization purposes.
After you do this your app should run fine. At this point your task is pretty much accomplished and your app should run fine with a new model name and new table name. The only problem you will run into using South is the next time you create a migration using it's auto detection feature it will try to drop the old table and create a new one from scratch because it has detected your new model name. To fix this you need to create another custom migration:
python manage.py schemamigration xyz tell_south_we_changed_the_model_name_for_old_model_name --empty
The nice thing is here you do nothing since you have already changed your model name so South picks this up. Just migrate with "pass" in the migrate forwards and backwards:
python manage.py migrate xyz
Nothing is done and South now realizes it is up to date. Try:
python manage.py schemamigration xyz --auto
and you should see it detects nothing has changed