A pythonic way to do this would be extremely useful if it existed. As you
suggested, I did this using a sql exclusion constraint statement on the
table and a migration.
For example:
000x_your_migration_name.py
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from django.db import migrations
SQL = """ALTER TABLE your_table DROP CONSTRAINT IF EXISTS
range_overlap_exclusion;
ALTER TABLE your_table ADD CONSTRAINT range_overlap_exclusion
EXCLUDE USING gist (resource WITH =, date_range WITH &&);"""
class Migration(migrations.Migration):
dependencies = [
('module_name', '000x_previous_migration'),
]
operations = [migrations.RunSQL(sql=SQL,
reverse_sql=migrations.RunSQL.noop), ]
On Sunday, October 1, 2017 at 11:53:53 PM UTC+2, Brylie Christopher Oxley
wrote:
>
> Now that Django supports the DateRangeField, is there a 'Pythonic' way to
> prevent records from having overlapping date ranges?
>
> # Hypothetical use case
> One hypothetical use case would be a booking system, where you don't want
> people to book the same resource at the same time.
>
> # Hypothetical example code
> <!-- language: lang-py -->
>
> class Booking(models.model):
> # The resource to be reserved
> resource = models.ForeignKey('Resource')
> # When to reserve the resource
> date_range = models.DateRangeField()
>
> class Meta:
> unique_together = ('resource', 'date_range',)
>
> This might have the effect of adding an exclusion constraint on the
> underlying table:
>
> https://www.postgresql.org/docs/9.3/static/sql-createtable.html#SQL-CREATETABLE-EXCLUDE
> --
> Sent from my Android device with K-9 Mail. Please excuse my brevity.
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