django 迁移 - 重新创建数据库

Question

I am running python 2.7 and django 1.8.

I have this exact issue.

The answer, posted as a comment is: What I did is completely remake the db, erase the migration history and folders.

I am very uncertain about deleting and creating the database.

I am running a PostgreSQL database. If I drop/delete the database and then run the migrations, will the database be rebuilt from the migrations? I don't want to delete the database and then be stuck in a worse situation.

Answer 1

Here is what I did to correct this issue:

First, make a script of the data, so that when the database is destroyed and re-created, the data can be easily re-created.

Next run the following script to reset the database (this will delete all the db data and remove the db tables).

Then run the following script to recreate the db:

python manage.py reset_db

Then, run the following script to re-create the db:

python manage.py migrate

Next, run the script to create the database data.

Finially, run the following script to start the server:

python manage.py runserver

That is it.

I hope that this helps some one out there.

Answer 2

In fact there is no need to do that, but in order to make sure you are doing right take following things into consideration:

1. Make sure your DB is not being accessed (Written) by a process or your app during the migrations process. I had a lot of troubles with that.

2. If your server is running, make sure to turn it off. There are some issues that prevent the migrations or updating the results while the server is running, in particular in production mode.

3. If you are migrating in production after migrating in development mode, make sure that there are no files from the development. They are name similarly, so the system throws an error about migrations already exist.

4. Remember about default values. If you are migrating in order to include a new column in a pre-existent table, you must provide a default value to fill those rows in the new column.