Django Shell

But how would you practically populate your data base if you had 1000s or millions of sample rows?

Good question! As a beginner project, this assumes that you’re building a small example project and that you’ll fill up your DB as you build out your portfolio.

However, Django does have capabilities to integrate with an existing database, and since it’s all Python code, you could also write a custom script that fetches the data from your source and funnels it into your project’s DB.

Wait. You copied image files from your own server, which, of course, I can’t do. How can I get copies of those? It is really important to me that I can replicate what your are demonstrating.

@reblark: I took some screenshots right on my computer and moved those files into the Django folder structure that you see above. The path that you see points to the relative path in the Django project. This could be any image file that you have locally, you just need to make the names match.

OK. I don’t see the screenshots or the structure and I apologize for not being able to keep my comments in synch but it is difficult only being able to communicate through a specific session. It’s 11/4 at 11:00 AM PST, and I just wanted you to know that I worked through the PyCharm database problem. On the one hand, it is very frustrating. On the other hand, figuring things out is very rewarding. It’s all effing crazy.

Are there any ways by which we can enter data through frontend interface?

Yes, you can use the Admin Interface that comes provided with a Django app.

Otherwise, you’ll have to built your own Django Forms to collect user input.

The database doesn’t work in my project. This is how the Django shell looks:

from projects.models import Project p1 = Project(title=”test project”,description = “This is a test, 1234”,technologi=”Django”, image=”F-01.jpg”) p1.save <bound method Model.save of <Project: Project object (None)>>

Her somtething seems to have gone wrong. Anyway I continued. But nothing seems to have been inserted into the database: *>>> results = Project.objects.all()

results <QuerySet []>

*

I’m sorry! I found that I had spaces in the “project.models” command. Also I forgot the () after the p1.save. Now everything is working fine.

1) When you write p1 = Projects(title=’test project’, ....)

where is the model.Models argument of Projects class?

Also, another question.

2) In Projects class declaration, variables: title, escription, technology, image shouldn’t be self.title, self.escription, self.technology, self.image instead?

Hi @koutsellisthemistoklis!

1) Inheritance

What you are doing with the below code:

from django.db import models

class Project(models.Model):
    # your code

is that you are inheriting properties from Django’s Model class to the new model you are creating. Therefore, models.Model is not an argument that you would need to pass when creating an instance of a class. Classes work differently in this than functions do. Check out our article on Inheritance and Composition: A Python OOP Guide and the section in our associated course.

2) Missing self in Django Models

The very stripped-down and somewhat unusual way of defining a class in a Django model is due to the fact that Django has metaclasses that actually take on the work of creating your class.

This allows the class definition to be so clean and easy. Note that you also don’t have to write an explicit __init__() method for a model class.

All this is thanks to metaclasses and Django’s gargantuous workload behind the scenes that aims to make webdev easier for you :)

(InteractiveConsole)

from projects.models import project Traceback (most recent call last): File “<console>”, line 1, in <module> ImportError: cannot import name ‘project’ from ‘projects.models’ (C:\Users\Dell\PycharmProjects\django-portfol io\projects\models.py)

please how can i resovle this thanks to progress

Hi @okorobright13! Looks like this might be a typo. Your Project model should be capitalized instead of in lowercase.

You want to import the Project class that you defined in projects/models.py, therefore your import statement needs to make sure it can actually find it. Computers are very literal with spelling and capitalization, so it’ll only find it if it matches exactly :) Hope that fixes it!

Martin Breuss,thanks alot you are right is working now and i’m in progress for now,hahahahaha message error is our friend!!!!!1

>>> p1 = Project(title="test project", description="this is a test 1234!", technology="Django", image="avatar.jpg"
... p1.save()
  File "<console>", line 2
    p1.save()
     ^
SyntaxError: invalid syntax

What is going on there? I’ve been staring at it for a long time, and I can’t find the error.

Nevermind. I found the error. It turns out you have to be very precise with parenthesis and notation! =oP

It’s a tricky one, because the arrow doesn’t point in the right place here.

Check the end of the line above where the ^ is pointing to, there’s a little thing missing…

You can notice that there’s something wrong by how the prompt starts the line where you’re writing p1.save(), it should start with a >>>, but insteads starts with a .... The thee dots mean that it’s continuing the line above.

Hope that helps you find it! :)

Hey! So I have a weird question. So in the part after p1.save() I did results = project.objects.all and when I did >>>results I got this : <bound method BaseManager.all of <django.db.models.manager.Manager object at 0x03B899D0>>

I realise my mistake was not adding the () at the end and everything was fine. So my question is what does the () tell python to do? I tried googling what the shell spit out the time I did the command without () but I couldn’t find anything too helpful. Could someone explain to me I am just very curious.

Hi @c4inmypants and nice job figuring it out and staying curious :)

The short answer to your question is that in Python, the () execute a function or a method.

Functions And Methods

Functions and methods have some, well, functionality encoded in them that can be accessed by calling them. That’s why using the () at the end of their name is called a Function Call. In your case, to be all the way precise, you’d have to talk about a “method” instead of “function” because the code that does the work is dependent on a specific object. 🙄 Don’t worry about that too much, however, for this situation, that’s mostly terminology. But if you want, you can read more about Difference Between a Method And a Function.

Your Example

So when you read that the () execute the method, it might make you think that there needs to be something to execute. That is the object that you are referring to and that contains the code logic. Let’s look at your example, stripped away from the variable assignment:

project.objects.all

Here you are referencing the all method on your projects.objects object, but you are not calling it. For all that Python knows, you want to access the method, and not to execute it. So it does your bidding and tells you what you got:

<bound method BaseManager.all of <django.db.models.manager.Manager object at 0x03B899D0>>

You can dive deeper into this output and learn a fair bit from it, but the main take-aways for this example are:

1. Reference, not execution: When leaving out the brackets, Python gives you access to the bound method BaseManager.all of some object that lives in your computer’s memory
2. Execution: If you want to make the method do its job, you need to call it, which you do by adding the () at the end, e.g.:

projects.objects.all()

The instructor set the query to p1 so after running: p1 = Project(title="test project", description="this is a test 1234!", technology="Django", image="testproject.png")

Run: p1.save()

Then: p1

The error message is:

from projects.models import Projects
Traceback (most recent call last):
  File "<console>", line 1, in <module>
ImportError: cannot import name 'Projects'

What I’m doing wrong?

@alazejha Hi. Without seeing your code, it’s hard to tell, but it might be a simple typo error. Are you importing the class Project or Projects?

Just curious if there’s an easy way to see everything in the query object. So in this lesson you could do this:

>>> res = Project.objects.all()
>>> print(f'title={res[0].title}, description={res[0].description}, technology={res[0].technology}, image={res[0].image}')

That’s pretty tedious though. The only thing I can think of is to peek inside the object and filter out private attributes:

>>> {k: v for k, v in res[0].__dict__.items() if not k.startswith('_')}

Is there a better way or if you want to peek inside the database you should a database tool instead?

@jamesrsmall Normally you’d use a dataclass, which implements the string representation out of the box:

>>> from dataclasses import dataclass
>>> @dataclass
... class Project:
...     name: str
...     age: int
... 
>>> Project("foobar", 42)
Project(name='foobar', age=42)

Since Django models use descriptors, they aren’t compatible with dataclasses. However, you could try whipping up a custom mixin class to encapsulate your logic:

class ReprMixin:
    def __repr__(self):
        attrs = ", ".join([
            f'{name}="{getattr(self, name)}"'
            for name in vars(self) if not name.startswith("_")
        ])
        return f"{self.__class__.__name__}({attrs})"

class Project(ReprMixin, models.Model):
    name = models.CharField(max_length=20)
    age = models.IntegerField()

Then, in your Django shell:

>>> from projects.models import Project
>>> Project.objects.first()
Project(name="foobar", age="42")

Note that this code snippet is super simple and doesn’t account for recursive traversal or even handling different data types. I used to have a thorough implementation of this in one of my projects, but can’t find it anymore.

There are plenty of third-party libraries on PyPI that may do what you’re looking for. Try searching for “repr” or “str”.

@Bartek - very cool, thanks! I appreciate the example and links.

Hi, I’m facing some difficulties having the “daily”, “test project”, “todo” images appear in the img file. I’ve completed as instructed the double file projects>img but no images, through my desktop I can see the files are present in my django portfolio>projects>static>projects>img file so not sure what’s causing the no show in my virtual environment.

For this command I keep getting this error. I’m not exactly sure on how to proceed. “Model class projects.models.Project doesn’t declare an explicit app_label and isn’t in an application in INSTALLED_APPS.”

@crispineda34 If you google that error message and follow the first search result, you’ll land on a StackOverflow question, which seems to have the right answer for you:

Are you missing putting in your application name into the settings file? (…)

I can’t get pass this:

from projects.models import Project
>>> p1 = Project(title='test project', description='this is a test, 1234!', technology='Django', image='testproject.png')
>>> p1.save()
Traceback (most recent call last):
  File "C:\users\apple\documents\django-portfolio\.env\lib\site-packages\django\db\backends\utils.py", line 84, in _execute
    return self.cursor.execute(sql, params)
  File "C:\users\apple\documents\django-portfolio\.env\lib\site-packages\django\db\backends\sqlite3\base.py", line 423, in e
xecute
    return Database.Cursor.execute(self, query, params)
sqlite3.OperationalError: no such table: projects_project

# models.py

class Project(models.Model):
    title = models.CharField(max_length=100)
    description = models.TextField()
    technology = models.CharField(max_length=20)
    image = models.FilePathField(path='/projects/img')

Thanks!

Nevermind, I found the problem

Wonderful course :) I have a question: Why is the path to the image in models.py not projects/static/projects/img And instead is /projects/img

Here is the entire code in projects/models.py, I am referring to the last line:

from django.db import models

class Project(models.Model):
    title = models.CharField(max_length=100)
    description = models.TextField()
    technology = models.CharField(max_length=20)
    image = models.FilePathField(path="/projects/img")

Thank you!

@mochibeepboop Great question! It’s because Django automatically looks for static files in each application’s static/ folder, so you only need to provide a path relative to it.

Thank you for your response @Bartosz Zaczyński! So do we essentially get ‘projects/static/’ for ‘free’? Meaning Django prepends this part of the path in the background?

@mochibeepboop Yes, that’s exactly right.