- What is SQLAlchemy? 6:37
- Creating a Model 8:37
- Creating a Movie Model 3 objectives
- Create and Read with SQLAlchemy 8:57
- ORM, Models, and Creation 6 questions
- Update, Rollback, and Delete 11:32
- Movie Database Continued 4 objectives
- Querying 15:18
- Querying the Movie Database 2 objectives
- SQLAlchemy Fundamentals 5 questions
Preview
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What is SQLAlchemy?
6:37An introduction to SQLAlchemy, the Python ORM.
[MUSIC]
0:00
Hi there, my name is Megan and
I'm a teacher here at Treehouse.
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My pronouns are she, her, hers.
0:13
In this course,
I'm excited to show you SQLAlchemy.
0:16
SQLAlchemy is an O-R-M, or
object-relational mapper.
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It's a Python code library that
transfers data stored in a SQL
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database into Python objects.
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You can then use Python code to create,
read, update, and
0:35
delete data instead of writing
straight SQL, which helps speed up
0:39
development time, especially for
developers who are not fluent in SQL.
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And it can often make managing
data less error prone.
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SQL stands for Structured Query Language.
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It's a language for
interacting with relational databases.
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Relational databases are structured like
a traditional table with columns and rows.
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If you're not familiar with SQL,
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I highly suggest taking a peek at
the prerequisites for this course.
1:10
I've also listed them in
the teacher's notes below.
1:15
This prior knowledge will bridge the gap
between working with the database using
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SQL, and working with the database
using Python's SQLAlchemy.
1:24
If you would like to follow along
in workspaces, then go ahead and
1:29
open up the workspace
attached to this video.
1:32
In the console,
run pip install sqlalchemy,
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hit Enter, let it download and
you're all set.
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If you would like to follow along locally,
create a folder for your project and
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open it in your IDE of choice.
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I'm going to use Visual Studio.
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Let me go ahead and
create our models.py file.
2:04
We'll need to download SQLAlchemy,
so we can use it.
2:08
But first,
let's create a virtual environment.
2:13
Create a virtual environment by
running python if you're on Windows,
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and python3 if you're on a Mac like I am,
-m venv env.
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And this will start your
virtual environment.
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You can see it's asking if
I want to use it, I do.
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And you see our folder
up here was created, and
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VS Code also adds its own little thing,
you don't need to worry about it.
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Okay, now that we have our
virtual environment created,
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we need to activate it.
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Now, if you're on Windows,
you need to write and
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I need to make sure I get
my slashes correctly,
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.\env\Scripts\activate.
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If you're on Windows.
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If you're on Mac,
then you need to write it
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as source ./env/bin/activate.
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And this is all in the teacher's
notes below as well.
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So you can reference it at any time.
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So go ahead and type that out,
whichever one you need, hit Enter.
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And now you can see I have this env here,
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because I am now inside of
my virtual environment.
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Perfect, now we can install SQLAlchemy.
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Same install, pip install sqlalchemy.
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Awesome, and
then we can run pip freeze, caret or
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arrow to the right, requirements.txt.
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This is the file that will
be important for others.
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And if I run it, it will create this file.
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And if I click into it, it'll tell
me sqlalchemy has been installed.
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And this is the version
that I'm currently using.
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Our requirements file is ready.
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If you want to create a repo for
this project and
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others end up wanting to run your project
to check it out, they will need this file.
4:23
If you do wanna post this on GitHub,
then let's also create a gitignore file.
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New File > .gitignore.
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Inside, we're going to write env.
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This will make sure that environment
folder does not get shared to your repo.
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You don't want that to go up.
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We can also do this, .vscode.
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If you're like me and
you're working in vs code,
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we don't need that to go up either.
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That's just for us locally here.
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There's also this .DS_Store on Macs
that sometimes gets pushed up.
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You don't want those to go either, so
you can add that to your gitignore file.
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And that should be good for right now.
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The most important one is
your environment folder.
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This has a whole bunch of downloads in it,
and anyone running your project only
5:15
needs the requirements file to download
those requirements themselves.
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So we don't wanna send them all of
our files, they can download it for
5:25
themselves.
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Okay, cool.
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Now that you have either workspaces or
your local environment set up,
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let's check our version
in the Python shell.
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I'm gonna run a clear.
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Then I'm gonna go python3 to make sure
I'm in the newer version of Python.
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And then I'm gonna import at
the top sqlalchemy, awesome.
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And then I'm going to run
sqlalchemy.__version__.
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And awesome, it's the same version
that's in our requirements file,
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but this is another way that you
can check your version number.
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You can see I'm on version 1.3.22.
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And your version may be different and
that's okay,
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technologies change quite frequently.
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So if you're on a newer version than I am,
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make sure to check the teacher's
notes throughout the course.
6:25
This way, you get the most up-to-date
information to go along with your version.
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We're all set, time to dive in.
6:34