How do I seed a flask sql-alchemy database

Question

I am new at python, I just learnt how to create an api using flask restless and flask sql-alchemy. I however would like to seed the database with random values. How do I ach

Answer 1

I had a similar question and did some research, found something that worked.

The pattern I am seeing is based on registering a Flask CLI custom command, something like: flask seed.

This would look like this given your example. First, import the following into your api code file (let's say you have it named server.py):

from flask.cli import with_appcontext

(I see you do import flask but I would just add you should change these to from flask import what_you_need)

Next, create a function that does the seeding for your project:

@with_appcontext
def seed():
   """Seed the database."""
   todo1 = TodoItem(...).save()
   todo2 = TodoItem(...).save()
   todo3 = TodoItem(...).save()

Finally, register these command with your flask application:

def register_commands(app):
    """Register CLI commands."""
    app.cli.add_command(seed)

After you've configured you're application, make sure you call register_commands to register the commands:

register_commands(app)

At this point, you should be able to run: flask seed. You can add more functions (maybe a flask reset) using the same pattern.

Answer 2

From another newbie, the forgerypy and forgerypy3 libraries are available for this purpose (though they look like they haven't been touched in a bit).

A simple example of how to use them by adding them to your model:

class TodoItem(db.Model):

    ....

    @staticmethod
    def generate_fake_data(records=10):
        import forgery_py
        from random import randint
        for record in records:
            todo = TodoItem(todo=forgery_py.lorem_ipsum.word(),
                            due_date=forgery_py.date.date(),
                            priority=randint(1,4))
            db.session.add(todo)
        try:
            db.session.commit()
        except:
            db.session.rollback()

You would then call the generate_fake_data method in a shell session.

And Miguel Grinberg's Flask Web Development (the O'Reilly book, not blog) chapter 11 is a good resource for this.