Hi, Sorry but a need to return to this
El jueves, 20 de octubre de 2016, 9:53:23 (UTC-3), Tim Graham escribió: > > The 'default' model field option is used in Python rather than in the > database. SchemaEditor might set a column default to ease populating a > value on existing rows but that default shouldn't be left in the column's > definition. self.assertIsNone(field.default) means that the column > doesn't have a default. > Ok, you say that SchemaEditor set a column default to ease populating a value on existing row. Which sql engine works in that way? I was reading into postgresql docs [1] and it says that add a column default definition "Note that this doesn't affect any existing rows in the table, it just changes the default for future INSERT commands.". So, I don't undertend why add a database default definition is useful if later we need to remove it. > > > On Thursday, October 20, 2016 at 8:29:29 AM UTC-4, Maximiliano Robaina > wrote: >> >> Hi Tim, >> >> Thanks for response. >> >> El martes, 18 de octubre de 2016, 12:07:34 (UTC-3), Tim Graham escribió: >>> >>> Hi Maxi, >>> >>> Did you take a look at the relevant commit that introduced the flag? >>> >>> https://github.com/django/django/commit/75303b01a9cc900eebf1f27ba0bc6508334242fc >>> >> >> Yes, I was looking into this changeset, but I can't understand yet what >> "And that the default is no longer set in the database." means in >> test_add_field_default_dropped [1]. >> field.default contains the column default definition not the default >> value of the some table record, Is it that correct?, So, why this must be >> None? >> >> >> >> [1] >> https://github.com/django/django/commit/75303b01a9cc900eebf1f27ba0bc6508334242fc#diff-888b45a0a8f38ee67e8d22403cf994dbR1371 >> >> >> Regards >> >> >> >>> >>> On Tuesday, October 18, 2016 at 9:51:46 AM UTC-4, Maximiliano Robaina >>> wrote: >>>> >>>> Hi, >>>> >>>> How supposed to can_introspect_default must work? >>>> >>>> I'm working on django firebird backend and I'm trying to figured out >>>> how this feature works, but the schema tests fails. >>>> This default is at database level or django level? >>>> >>>> If I define a field with a default value, and do a metadata >>>> introspection over this field to know if default value is defined, it >>>> always returns True. >>>> >>>> I hope be clear (sorry for my bad english) >>>> >>>> --- >>>> Maxi >>>> >>> -- You received this message because you are subscribed to the Google Groups "Django developers (Contributions to Django itself)" group. To unsubscribe from this group and stop receiving emails from it, send an email to django-developers+unsubscr...@googlegroups.com. To post to this group, send email to django-developers@googlegroups.com. Visit this group at https://groups.google.com/group/django-developers. To view this discussion on the web visit https://groups.google.com/d/msgid/django-developers/df9f8a7d-eba6-4108-9506-a3a69e2edc0e%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
