Its unclear what you mean by "last ID" - and I cannot see the value of storing such as they are available in the database...
But have a look at https://stackoverflow.com/questions/12649659/how-to-set-a-django-model-fields-default-value-to-a-function-call-callable-e The example is: from datetime import datetime, timedelta # default to 1 day from now def get_default_my_date(): return datetime.now() + timedelta(days=1) class MyModel(models.Model): my_date = models.DateTimeField(default=get_default_my_date) Instead of the date arithmetic, you'd need to write code to, for example, extract last ID from the database (assuming you have an auto-increment ID set) and do the concatenation. On Thursday, 7 May 2020 02:23:22 UTC+2, Anselme SERI wrote: > > Thanks you for your answer. I know how to make a default value in > charfield but I don't know how to build function which returns value for > my default field. In my case this function must retrieve last id on my > model and must concataned it with a string and the final result must be > affected to default charfield. Have you an example ? Help me plz. > > Le mer. 6 mai 2020 à 18:44, Motaz Hejaze <[email protected] <javascript:>> > a écrit : > >> Yes you can make a normal charfield and assign its default attribute to a >> function you declare >> >> On Wed, 6 May 2020, 6:53 pm Anselme SERI, <[email protected] >> <javascript:>> wrote: >> >>> Hi, >>> >>> I use Django 3.0 and I would like to create a function which fill >>> automatically a field in my models. >>> Can I do it directly in models.py ? How? >>> >>> Thanks a lot >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "Django users" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected] <javascript:>. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/django-users/5f810453-c7ca-4c10-bca1-4cfe11ea496a%40googlegroups.com >>> >>> <https://groups.google.com/d/msgid/django-users/5f810453-c7ca-4c10-bca1-4cfe11ea496a%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> >> -- >> You received this message because you are subscribed to the Google Groups >> "Django users" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected] <javascript:>. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/django-users/CAHV4E-dDRD%3DLteuDo7KuATzjKem-ThvtozzHuaqkwAeAC%2BBrZw%40mail.gmail.com >> >> <https://groups.google.com/d/msgid/django-users/CAHV4E-dDRD%3DLteuDo7KuATzjKem-ThvtozzHuaqkwAeAC%2BBrZw%40mail.gmail.com?utm_medium=email&utm_source=footer> >> . >> > -- You received this message because you are subscribed to the Google Groups "Django users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/48c4d59e-8241-4739-b8df-feab45a7fa3a%40googlegroups.com.
