如何避免ProgrammingError:在将Django模型实例保存到远程数据库时无法调整'DateTimeRangeField‘类型？

Question

我有一个包含DateTimeRangeField的模型，如https://docs.djangoproject.com/en/1.8/ref/contrib/postgres/fields/#defining-your-own-range-types中所描述的，请参见下面的内容：

models.py

from django.db import models
from django.contrib.postgres.fields import DateTimeRangeField, RangeField

class ReportPeriod(models.Model):
  id = models.IntegerField(primary_key=True)
  period_name = models.TextField(blank=True)
  active_range = DateTimeRangeField(blank=True) 
  class Meta:
    managed = False
    db_table = 'report_period'

当我使用它查询远程数据库时，模型工作得很好(例如，ReportPeriod.objects.using('remote_db').filter(id='1',active_range__contains=datetime.now())返回预期的QuerySet)。

但是，当我试图在我的视图或shell中保存一个新的ReportPeriod时，我会得到一个ProgrammingError: can't adapt type 'DateTimeRangeField'。下面是我在获得错误之前在shell中遵循的步骤：

new_period = ReportPeriod(id=1,period_name = 'morning',active_range = DateTimeRangeField(datetime(2015,1,1,0,0,0),datetime(2016,1,1,0,0,0)))
new_period.save(using='remote_db')

这是整个错误跟踪：

Traceback (most recent call last):
 File "<console>", line 1, in <module>
 File "~/.virtualenvs/mve/lib/python2.7/site-packages/django/db/models/base.py", line 710, in save
force_update=force_update, update_fields=update_fields)
 File "~/.virtualenvs/mve/lib/python2.7/site-packages/django/db/models/base.py", line 738, in save_base
updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields)
 File "~/.virtualenvs/mve/lib/python2.7/site-packages/django/db/models/base.py", line 803, in _save_table
forced_update)
 File "~/.virtualenvs/mve/lib/python2.7/site-packages/django/db/models/base.py", line 853, in _do_update
return filtered._update(values) > 0
 File "~/.virtualenvs/mve/lib/python2.7/site-packages/django/db/models/query.py", line 580, in _update
return query.get_compiler(self.db).execute_sql(CURSOR)
 File "~/.virtualenvs/mve/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 1062, in execute_sql
cursor = super(SQLUpdateCompiler, self).execute_sql(result_type)
 File "~/.virtualenvs/mve/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 840, in execute_sql
cursor.execute(sql, params)
 File "~/.virtualenvs/mve/lib/python2.7/site-packages/django/db/backends/utils.py", line 79, in execute
return super(CursorDebugWrapper, self).execute(sql, params)
 File "~/.virtualenvs/mve/lib/python2.7/site-packages/django/db/backends/utils.py", line 64, in execute
return self.cursor.execute(sql, params)
 File "~/.virtualenvs/mve/lib/python2.7/site-packages/django/db/utils.py", line 97, in __exit__
six.reraise(dj_exc_type, dj_exc_value, traceback)
 File "~/.virtualenvs/mve/lib/python2.7/site-packages/django/db/backends/utils.py", line 64, in execute
return self.cursor.execute(sql, params)
ProgrammingError: can't adapt type 'DateTimeRangeField'

我在模型定义中遗漏了什么吗？有人知道如何解决这个问题吗？

Answer 1

DateTimeRangeField是字段类，应该仅用于模型定义。若要创建具有日期范围的对象，应使用来自DateTimeRange的psycopg2.extras类。

from psycopg2.extras import DateTimeRange

new_period = ReportPeriod(
    id=1,
    period_name='morning',
    active_range=DateTimeRange(datetime(2015, 1, 1, 0, 0, 0), datetime(2016, 1, 1, 0, 0, 0))
)
new_period.save(using='remote_db')

django.contrib.postgres文档中没有很好的文档，只显示了NumericRange，但我找到了这个用法示例在DateTimeRangeField测试中。