I'm new django web framework. I have a models.py file where i given information about my entity fields, i ran the manage.py migrate command table generated i have alter the table manually without touch the models.py later I have run the python manage.py inspectdb > myapp/models.py in controller level using os.system models.py updated then i have tried models.objects.all() I'm unable to get the newly added field, I have called the view By using ajax call , after page refresh only new field name coming.
can you help how to get all field names with in the ajax response only with out page refresh. It would be grateful if you can help me
Note: I have checked in view level only with out page refresh first time only new column not came after page refresh it came
Thanks in advance...
I'm looking for cache in django
Before migrating, you need to create migrations.
If your DB is correctly configured, here you are (python3/python depending on version that you are using):
First: python3 manage.py makemigrations
Second: python3 manage.py migrate
makemigrations creates SQL queries, and migrate runs it. You can read more here: Django 1.8 - what's the difference between migrate and makemigrations?
Related
I'm doing and playing around with my own Django project.
I tried to change a couple of names of fields in models.py and tried some ways that I found on google.
The way I did was just to change the name of the field and do make migrations on command line. Once I did it, it asked if I want to rename the original field into the new name of the field, and I just responded yes and migrate it.
But I figured out it's not working out as it had been so I checked my administration page on Django and DB Browser for SQLite and found that all data of the field I changed in the name have been also changed into the name of changed field name that I tried as shown in the picture.
(i.e. I changed field called ingredient into Essential_ingredient. However, all of its data also changed into essential_ingredient, just lowered-cased name of changed field name)
Does anyone know how to retrieve or bring back my old data?
Thanks in advance!
Picture of changed name of the field and its data in models.py:
Hi you can perform below step to get new and fresh db schema.
python manage.py migrate --fake myApp zero
then delete all migration file in every folder and see migration using below command
python manage.py showmigrations
and then do
python manage.py makemigrations
python manage.py migrate --fake-initial
For more info you can follow below links.
https://www.techiediaries.com/how-to-reset-migrations-in-django-17-18-19-and-110/
https://simpleisbetterthancomplex.com/tutorial/2016/07/26/how-to-reset-migrations.html
I changed a database view from DateField to DateTimeField but when I run ./manage.py makemigrations it says "No changes detected"
Any ideas on how to do properly update my database view?
Ok so since views are not managed, the right way to do this is by manually creating a *migration.py file and that the changes to the view there. Once that is done the makemigrations and migrate commands will pick it.
I have a django 1.8 app working with a db.
I'm trying to change the schema of a table using the built-in migration.
Here are the steps I did:
In my dev invironment, I grabbed the app source and ran
python manage.py sycdb
then I ran
python manage.py loaddata ~/my_data.json
then I modified modes.py. Added a field and renamed a field...all from the same table 'TABLE1' which had no data.
then
python manage.py makemigrations myapp
python manage.py migrate
Error: django.db.utils.OperationalError: table "myapp_someother_table" already exists
then ran
python manage.py migrate --fake-initial
worked!
but when I browsed to the admin page for TABLE1, I get this error:
OperationalError: no such column: myapp_table1.my_new_field_id
I checked the db and yes, there is no such column.
How can I procceed from here? I prefer to fix this via django.
If I fix it straight in the db, then the migration goes out of sync.
Migrations do not automagically see that you have made changes. Migrations detect changes by comparing the current model with the historical model saved in the migration files.
In this case, you didn't have any historical models, since you didn't have any migrations. Django was not able to detect any changes in your models, even though they were different from your database.
The correct way to make changes to your model is to first run manage.py makemigration <my_app>, and then make the changes to your model, followed by another manage.py makemigrations.
You might not be able to do it via pure django and keep your data. I don't have personal experience with south but there are a lot of mentions if this tool. Just in case if nothing else works for you...
Here is what I did to make things work, but there must be a better way so please add more answers/comments...
I deleted the sqlite db and the migration folder
I made the desired changes to model.py
ran syncdb
ran loaddata to load the json data dump that I had saved previously.
just started the dev server
I made a change to my models, and I cannot for the life of me figure out how to get my database to reflect my models. So far I have tried the following:
python manage.py shelldb
SELECT * FROM sqlite_master WHERE type='table';
DROP TABLE appname_modelname;
When I tried that I got: "unknown command: shelldb".
I also tried:
python manage.py dbshell
DROP TABLE accounts_userreview;
No error, but my db still doesn't reflect my models.
Finally, I just altogether deleted my database by dragging it into the trash and then doing syncdb, it then made me create a new superuser, but STILL the database that was created does not reflect the changes to my models.
I'm at a loss here, What else can I do here? Also, I'm new to learning Django, is there some kind of layer in between the models and my database? I would assume there is since deleting and then rebuilding the database didn't work.
Would appreciate any advice here.
if you are on Django < 1.7 , you have to use some migration tool i.e. - South . Django 1.7 has inbuilt migration.
For more info migrations
Run these commands in terminal to make migrations for Django 1.7
python manage.py makemigrations
python manage.py syncdb
for Django < 1.7
use South
I'm using sqlite3 and pycharm to learn more about django, and googled to find that south is recommended to make it easier to modify models after they have been created.
I'm trying to follow the advice on http://south.aeracode.org/docs/tutorial/part1.html#starting-off.
The most success I've had so far is to create a simple model and run syncdb before adding south to installed_apps. That way the intial tables are created and I get a chance to create a super user. (Django admin seems to fret if there are no users).
Then I add south to installed_apps, and run django_manage.py schemamigration bookmarks --initial
It seems to work fine. A new directory is created called migrations with a couple of files in it in my app folder and an encouraging message.
"Created 0001_initial.py. You can now apply this migration with: ./manage.py migrate bookmarks"
The next step - django_manage.py" migrate bookmarks generates the following error message
django.db.utils.DatabaseError: no such table: south_migrationhistory.
I thought that table would be created in the first schememigration step. What am I missing? Can anyone help?
Marg
South uses a table if its own to keep track of which migrations have been applied. Before you can apply any migrations, this must have been created, using python ./manage.py syncdb.
As well as for setting up south, you will find syncdb sometimes necessary for non-south apps in your project, such as the very common django.contrib.auth.
Note that as a convenience, you can run both in one go like this
python ./manage.py syncdb --migrate
My latest (unsuccessful) effort was the following
Create application – synch db – superuser created
Test run –admin screen shows basic tables
Add south, and syncdb from command line with manage.py syncdb – south_migrationhistory table created. Add basic vanilla model
Tried various combinations of manage.py syncdb –manage, and
schemamigration from Pycharm (if run from within pycharm a
migrations directory is created within the app
– if run from the command line the directory does not seem to be
created.)
Django admin screen shows table – but if I try to edit
the table it says that it doesn’t exist
Check database structure
using SQLite browser - table for newly created model doesn’t exist
I’m starting to think that the whole thing is not worth the time wasting hassle – maybe I’m better off just modifying the tables in SQLite browser
Answer in the similar question:
Run syncdb to add the Django and South tables to the database.