Challenges with Migrations

So I am sitting in front of my laptop one day working on some issue. I remember it to be adding a database table. Since this is the first time I am actually creating a table I didn’t know how much this issue is going to haunt me! So I created a table SessionType just like other previously created tables and I make a PR happy to solve an issue. But just when I thought everything was going smooth this error comes up…

“Table session_type does not exist”

I understand that you have to again create the database so I run python create_db.py. But still I get the error. I search about it and find that every time I make changes to the database tables I have to update and generate a new migration script. Thus I run python manage.py db migrate and I get THE error:

“Cant locate revision identified by *some random revision number* ”

I literally went mad trying to solve this issue. Moreover whenever I would switch branches and the database tables were different I would get this error. Finally I found out a way to solve all the migration related problems (most of them :p). I added a script to drop the entire database.Since right now we are in the development stage it doesnt matter if the data in the database is deleted. So you run :

  1. python drop_db.py
  2. python create_db.py
  3. Use super_admin password to create the database
  4. But No! Migration is a little mean bastard!It wont leave you like that. You have to make the current revision and the head equal. Thus if your current is referring to some other revision ID then stamp the database table with the head.
  5. Run python manage.py db stamp head
  6. Now run python manage.py db migrate

 

Finally! The issue is solved. 🙂

 

 

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Better project definitions with User Stories and Themes

The Open Event project of FOSSASIA’s consists of a group of applications which involve making an application for managing events including the Open-Event Webapp, the Open-Event Android, Open-Event ios, and Open-Event Server of which I am working on.

The Open-Event Server is responsible for handling all the backend or the database aspect of the Open Event application. All the data for the application – the user details, the sessions details, the event details etc… is being managed by the server. But up till now we only had a basic working server with an prototype UI. In short not ready for people to use for their events . Thus my project was developed – Improving the Open-Event Organization project.

What is my project about?

The first versions of Open Event Server and the other subprojects – the Webapp and Android were not based on a user experience. So what we did this time was to create a user story for each of the projects. For the server, we created a user story wherein we decided what all functionalities will a user encounter when he /she uses our server. Thus step by step our project is being developed based on the user story created.

I have already solved a lot of issues which involve both – adding code to the backend as well as the frontend aspect. We have now a pretty good and properly functioning server with a login system involving Google and Facebook supported login. We also have a very awesome UI all thanks to gentelella. Presently we are working on the sessions part of the event creation wizard which is broken in various stages – Draft, Call for Papers, Schedule, Completed. The Draft part is almost finished and the Call for Papers part is going on.

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