1. Detailed explanation of commands
1. Act globally
python manage.py makemigrations means to inform Django about what to do, and to make a record, but it doesn't actually do it
python manage.py migrate actually starts creating the database
2. Act on app or file
It should be noted that these two commands act globally by default , that is, for all the latest changed models or
The migration file under migrations performs corresponding operations. If you want to only work on some apps, execute the following command:
python manage.py makemigrations appname
There is an additional 001_initial file under the makemigrations command file
The contents of this file indicate that we have created a model class Project, and pointed out the member attributes id, name, etc. and definitions of this class, and created model classes in models.py, one of which corresponds to a data table. This command does not actually add the database table
python manage.py migrate appname
Looking at the database at this time, the project table has been created in mysql
If you want to be precise to a certain migration file, you can use:
python manage.py migrate appname 0001_initial (filename)
2. Answers to questions
Because the data table has been generated before, or the command is executed again after modifying the content, it is found that it cannot be generated, for example:
Solution:
1. Delete the 001_initial file
2. Delete the records in the django_migrations table
Since a table django_migrations that comes with Django has added the previously generated table, such as
3. Re-execute the above two commands
python manage.py makemigrations appname
python manage.py migrate appname
Other bugs:
models.E028::: The same table name is used in multiple Model's db_table
1. Set managed=False in the meta class in the appname/models.py file
2. During operation, the model with managed=true will be detected to see whether multiple models use the same table name.
