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SQLAlchemy Basics

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What is SQLAlchemy?

6:37 with Megan Amendola

An introduction to SQLAlchemy, the Python ORM.

Pre-Requisites

Docs

It's always a good idea to bookmark the documentation for reference. SQLAlchemy Documentation

Local Setup Steps

  • Create a folder for your project
  • Open your folder in your IDE
  • Open the terminal in your IDE
  • Install virtual environment
    • Mac: python3 -m pip install --user virtualenv
    • Windows: py -m pip install --user virtualenv
  • Create a virtual environment
    • Mac: python3 -m venv env
    • Windows: python -m venv env
  • Activate your environment
    • Mac: source ./env/bin/activate
    • Windows: .\env\Scripts\activate
  • Install SQLAlchemy pip install sqlalchemy
  • Create requirements file pip freeze > requirements.txt

GitHub Resources

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    [MUSIC] 0:00
    Hi there, my name is Megan and I'm a teacher here at Treehouse. 0:09
    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. 0:21
    It's a Python code library that transfers data stored in a SQL 0:27
    database into Python objects. 0:31
    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. 0:43
    And it can often make managing data less error prone. 0:49
    SQL stands for Structured Query Language. 0:54
    It's a language for interacting with relational databases. 0:58
    Relational databases are structured like a traditional table with columns and rows. 1:02
    If you're not familiar with SQL, 1:08
    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 1:19
    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, 1:35
    hit Enter, let it download and you're all set. 1:41
    If you would like to follow along locally, create a folder for your project and 1:49
    open it in your IDE of choice. 1:54
    I'm going to use Visual Studio. 1:56
    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, 2:21
    and python3 if you're on a Mac like I am, -m venv env. 2:28
    And this will start your virtual environment. 2:33
    You can see it's asking if I want to use it, I do. 2:39
    And you see our folder up here was created, and 2:42
    VS Code also adds its own little thing, you don't need to worry about it. 2:44
    Okay, now that we have our virtual environment created, 2:52
    we need to activate it. 2:55
    Now, if you're on Windows, you need to write and 2:56
    I need to make sure I get my slashes correctly, 3:00
    .\env\Scripts\activate. 3:02
    If you're on Windows. 3:11
    If you're on Mac, then you need to write it 3:13
    as source ./env/bin/activate. 3:18
    And this is all in the teacher's notes below as well. 3:24
    So you can reference it at any time. 3:27
    So go ahead and type that out, whichever one you need, hit Enter. 3:30
    And now you can see I have this env here, 3:34
    because I am now inside of my virtual environment. 3:36
    Perfect, now we can install SQLAlchemy. 3:41
    Same install, pip install sqlalchemy. 3:43
    Awesome, and then we can run pip freeze, caret or 3:51
    arrow to the right, requirements.txt. 3:56
    This is the file that will be important for others. 4:00
    And if I run it, it will create this file. 4:04
    And if I click into it, it'll tell me sqlalchemy has been installed. 4:07
    And this is the version that I'm currently using. 4:11
    Our requirements file is ready. 4:17
    If you want to create a repo for this project and 4:20
    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. 4:28
    New File > .gitignore. 4:34
    Inside, we're going to write env. 4:38
    This will make sure that environment folder does not get shared to your repo. 4:40
    You don't want that to go up. 4:44
    We can also do this, .vscode. 4:47
    If you're like me and you're working in vs code, 4:50
    we don't need that to go up either. 4:54
    That's just for us locally here. 4:56
    There's also this .DS_Store on Macs that sometimes gets pushed up. 5:00
    You don't want those to go either, so you can add that to your gitignore file. 5:06
    And that should be good for right now. 5:11
    The most important one is your environment folder. 5:13
    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. 5:20
    So we don't wanna send them all of our files, they can download it for 5:25
    themselves. 5:29
    Okay, cool. 5:32
    Now that you have either workspaces or your local environment set up, 5:33
    let's check our version in the Python shell. 5:38
    I'm gonna run a clear. 5:42
    Then I'm gonna go python3 to make sure I'm in the newer version of Python. 5:43
    And then I'm gonna import at the top sqlalchemy, awesome. 5:49
    And then I'm going to run sqlalchemy.__version__. 5:56
    And awesome, it's the same version that's in our requirements file, 6:01
    but this is another way that you can check your version number. 6:07
    You can see I'm on version 1.3.22. 6:12
    And your version may be different and that's okay, 6:16
    technologies change quite frequently. 6:19
    So if you're on a newer version than I am, 6:23
    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. 6:29
    We're all set, time to dive in. 6:34

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