Makemigrations/migrate in django

Question

Could anyone help me solve this problem? I want to add data and time models in Django, but after makemigration, I got this.

**You are trying to add a non-nullable field 'MeterReading_DateTime' to mdm_api without a default; we can't do that (the database needs something to populate existing rows). Please select a fix:

Provide a one-off default now (will be set on all existing rows with a null value for this column)
Quit, and let me add a default in models.py Select an option:**

add ```null=True``` in the DateTime filed of the MeterReading model, otherwise, give it a default value. — Sumithran, May 17 '22 at 05:48
add default value as the field type and then run make migrations again — K.D, May 17 '22 at 05:55

score 1 · Accepted Answer · answered May 17 '22 at 06:29

Because it is a non-nullable field, It needs a default value to be set if there is a row without a value for that column.

The first point means, for the existing records, it will add a value for this field. The second point means, you have to give a default value which will be used for the existing records and also for the future records (unless you change it)

Either you add a null=True, give it a one-off default value, or add a default value in your model

Makemigrations/migrate in django

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