migrations | Automatic migration generation | Data Migration library

I'm thinking the suspect is an unsuccessful migration. Let's undo it and try again

change the posts migration post_id and author_id to this :

I solved my issue by using Docker Compose Wait. Essentially, it adds a wait loop that samples the DB container, and only when it's up, runs migrations and seeds the DB.

My next problem was: those seeds ran every time the container was run - I solved that by instead running a script that runs the seeds, and touchs a semaphore file. If the file exists already, it skips the seeds.

There are a couple of things to try out and fix:

You probably don't need the many2many attribute to load the DonationDetail slice, since they can be loaded only with DonationID. If you have a foreign key, you can add it like this:

The best idea is to keep production and development migrations the same and while developing you clean migrations before pushing the code and you should push migrations into your Version Control System too.

In development, you might end up deleting a table and re-creating it so make sure you don't push the un-intended migrations. The thing is you should treat migrations as code, not an automated script. I have done a lot of mistakes in the past, so, I came to the conclusion of including migrations in code. and that's effective and gives more control.

Moreover you might have to do data migrations in production, how will you do if you wont push the code?

Your problem is that you have set SESSION_CONNECTION=session, but your SESSION_DRIVER=default, so you have to use SESSION_DRIVER=database in your .env. See the config/session.php:

migrations.CreateModel does not create a model in the database upon instantiation. It is supposed to be present in the operations list where the migrations system will then use it to create the model. Furthermore you shouldn't be writing this migration manually anyway! Just write the code for the model in models.py:

You have to do this:

1. Why do you need to derive from Entity? these are POCO classes.
2. User and City have one-to-many relationship, right? then City needs to have list of Users.
3. In one-to-many entities it is typical to have ID field in addition to object itself. So, City would have CountryId.

Probably, put your DbContext class as well. And "Entity is just a parent with an ID". Huh? and how this ID will be generated - in addition to CityID, CountryID, etc.? You are really asking for trouble

Advice. I usually create a database with all the tables and foreign keys - and then run scaffolding to get the baseline of objects. Simplifies a lot!

Then start with that model, and make the needed changes, if any. Based on your code, I am not even sure that you will need any changes!