Code for Primary Key Switch

This is the repository for my blog entry on switch from one Primary Key to another.

To set it up, run pipenv install and create the file .env with providing the SECRET_KEY.

Initial Data

0000_base_db_dump_before_pk_switch.json contains a base dataset on which we can perform our migrations

0001_db_dump_after_pk_switch.json contains the data after the following migrations

Step1 - add uuid field

Create the new UUID field on our wanted Model (0002_testmodel_uuid.py), fill unique uuids (0003_set_unique_uuids) and rework null=True to unique=True (0004_set_unique_true_on_uuid)

Step 2 - add new ForeignKeys to other models

Create temporary FK field on other models which have already a FK relation to our TestModel, null=True (0005_testforeignkeymodel_test_model_uuid) is the key here, because we need to set the values directly in a migration (0006_uuid_fk_test_foreign_key_model)

Step 3 - add new Model for M2M

create a temporary Through Model for M2M relations (0007_testthroughmodel_and_more) and copy data

Step 4 - delete old connections

remove old connections (0009_remove_test_foreignkeymodel_test_model_and_more)

Step 5 - delete the db constrain an new FK fields

(0010_alter_test_foreignkeymodel_test_model_uuid_and_more)

Step 6 - set new pk field on TestModel

set the uuid field as new pk (0011_remove_testmodel_id_and_more)

Step 7 - rename fields, remove _uuid suffix

rename the fields and remove _uuid suffix - so these can be used as the fields before (0012_rename_test_model_uuid_testforeignkeymodel_test_model_and_more)

Step 8 - remove unecessary options change related name

remove unecessary options and change related name to the normal value (0013_alter_testforeignkeymodel_test_model_and_more)

MISC

if you don't want a ThroughModel you need to do the following 5 steps

Step 1 - add the "old" M2M

(0014_testmanytomanymdoel_test_models_old)

Step 2 - copy the values

(0015_copy_m2m)

Step 3 - delete the ThroughModel and M2M

(0016_remove_testmanytomanymodel_test_models_and_more)

Step 4 - rename the M2M

(0017_rename_test_models_old_testmanytomanymodel_test_models)

Step 5 - change back related_name

(0018_alter_testmanytomanymodel_test_models)