I have two database in mysql that have tables built from another program I have wrote to get data, etc. However I would like to use django and having trouble understanding the model/view after going through the tutorial and countless hours of googling. My problem is I just want to access the data and displaying the data. I tried to create routers and done inspectdb to create models. Only to get 1146 (table doesn't exist issues). I have a unique key.. Lets say (a, b) and have 6 other columns in the table. I just need to access those 6 columns row by row. I'm getting so many issues. If you need more details please let me know. Thank you.
inspectdb is far from being perfect. If you have an existing db with a bit of complexity you will end up probably changing a lot of code generated by this command. One you're done btw it should work fine. What's your exact issue? If you run inspectdb and it creates a model of your table you should be able to import it and use it like a normal model, can you share more details or errors you are getting while querying the table you're interested in?
Related
I am a newbie in programming, but now I connected my project with PostgreSQL. I learned the way to enter by SQL code and also found out that we can actually enter /adming (by creating the superuser and add data there). So which one is widely used in webdev?
It will depend completely on your application.
You can add rows to a table using SQL if that's the easiest way for you. Or you can add rows by creating new object instances in Python code and .save()ing them. Or you can create instances through a CreateView or through the Django admin.
Adding data with SQL has the drawback that you will lise the benefit of any validators declared on the model's fields. YOu may end up with data stored in your SQL tables which your app regards as "impossible", which may cause you minor or even major difficulties.
I have several times written management commands which all have the same general format. For each "row" in a data source (often a spreadsheet) construct one or more Django objects and save them. You can process each data "row" within a transaction (with transaction.atomic()) so if anything goes wrong, the data row is not committed. Or you can treat the entire process as a single transaction (not recommended for vast numbers of "rows", though)·
I have scraped data from a website using their API on a Django application. The data is JSON (a Python dictionary when I retrieve it on my end). The data has many, many fields. I want to store them in a database, so that I can create endpoints that will allow for lookup and modifications (updates). I need to use their fields to create the structure of my database. Any help on this issue or on how to tackle it would be greatly appreciated. I apologize if my question is not concise enough, please let me know if there is anything I need to specify.
I have seen many, many people saying to just populate it, such as this example How to populate a Django sqlite3 database. The issue is, there are so many fields that I cannot go and actually create the django model fields myself. From what I have read, it seems like I may be able to use serializers.ModelSerializer, although that seems to just populate a pre-existing db with already defined model.
Tricky to answer without details, but I would consider doing this in two steps - first, convert your json data to a database schema, for example using a tool like sqlify: https://sqlify.io/convert/json/to/sqlite
Then, create a database from the generated schema file, and use inspectdb to generate your django models: https://docs.djangoproject.com/en/2.2/ref/django-admin/#inspectdb
You'll probably need to tweak the generated schema and/or models, but this should go a long way towards automating the process.
I would go for a document database, like Elasticsearch or MongoDB.
Those are made for this kind of situation, look it up.
I'm working on a project that I inherited, and I want to add a table to my database that is very similar to one that already exists. Basically, we have a table to log users for our website, and I want to create a second table to specifically log users that our site fails to do a task for.
Since I didn't write the site myself, and am pretty new to both SQL and Django, I'm a little paranoid about running a migration (we have a lot of really sensitive data that I'm paranoid about wiping).
Instead of having a django migration create the table itself, can I create the second table in MySQL, and the corresponding model in Django, and then have this model "recognize" the SQL table? without explicitly using a migration?
SHORT ANSWER: Yes.
MEDIUM ANSWER: Yes. But you will have to figure out how Django would have created the table, and do it by hand. That's not terribly hard.
Django may also spit out some warnings on startup about migrations being needed...but those are warnings, and if the app works, then you're OK.
LONG ANSWER: Yes. But for the sake of your sanity and sleep quality, get a completely separate development environment and test your backups. (But you knew that already.)
This might sound like a bit of an odd question - but is it possible to load data from a (in this case MySQL) table to be used in Django without the need for a model to be present?
I realise this isn't really the Django way, but given my current scenario, I don't really know how better to solve the problem.
I'm working on a site, which for one aspect makes use of a table of data which has been bought from a third party. The columns of interest are liklely to remain stable, however the structure of the table could change with subsequent updates to the data set. The table is also massive (in terms of columns) - so I'm not keen on typing out each field in the model one-by-one. I'd also like to leave the table intact - so coming up with a model which represents the set of columns I am interested in is not really an ideal solution.
Ideally, I want to have this table in a database somewhere (possibly separate to the main site database) and access its contents directly using SQL.
You can always execute raw SQL directly against the database: see the docs.
There is one feature called inspectdb in Django. for legacy databases like MySQL , it creates models automatically by inspecting your db tables. it stored in our app files as models.py. so we don't need to type all column manually.But read the documentation carefully before creating the models because it may affect the DB data ...i hope this will be useful for you.
I guess you can use any SQL library available for Python. For example : http://www.sqlalchemy.org/
You have just then to connect to your database, perform your request and use the datas at your will. I think you can't use Django without their model system, but nothing prevents you from using another library for this in parallel.
I put my first Django site online eight months ago. It was both a proof of concept as well as my first experience with Django. Fast forward eight months, I have validated my idea, but since it was a proof of concept and my first Django project, the code is pretty messy. Essentially, I am going to be re-writing the majority of the site, including re-engineering the models.
This is all fine and good. I have all my new models planned out. Essentially, I am going to create a new database to develop off of and let South manage any new database schema changes I make.
It is important to note two things:
I will not be creating a new project, just a new database.
This will be the first time I am incorporating South into the project and I would prefer to start with fresh models and a fresh database.
My question is, when I create the new database, will importing the contents of the old auth_* and django_* tables into the new auth_* and django_* tables create any problems? I have had some users register using the original proof of concept and I don't want to lose their information. I've never had to do this before so I'm not sure if there will be any repercussions.
If you use sql dump, such as
mysqldump -uusername -ppassword db_name table_name > xxxx.sql
mysql -uusername -ppassword new_db_name < xxxx.sql
The database's side is fine，if your backend is some other db，you can still find the similar commands.
For a new db, i think you need to export/import auth_user, i'm not quite sure if you need other contents in django_* tables. You can do this step by step, and see whether the new project works.