Django: Change TimeField to DateTimeField in models.py

Question

In my models.py, i have some models with this kind of attributes:

timestamp = models.TimeField(default=0)

I want to change them to:

Answer 1

That's because time cannot be converted (casted) to timestamp (neither their time-zone related variants) in PostgreSQL. F.ex. this will also fail:

SELECT 'now'::time::timestamp

In these cases, you should use the USING clause in your ALTER TABLE statement (if you can edit it directly):

ALTER TABLE [ IF EXISTS ] [ ONLY ] name [ * ]
ALTER [ COLUMN ] column_name
[ SET DATA ] TYPE data_type [ COLLATE collation ] [ USING expression ]

Your query will look like, f.ex.:

ALTER TABLE "my_model"
ALTER COLUMN "column_name"
SET DATA TYPE TIMESTAMP WITH TIME ZONE USING 'yesterday'::date + "column_name"