Python 2.7 完整性错误-导入数据时get_或_create语句不能为NULL

我问我在哪里不知道如何正确使用外键。这一问题得到了很好的解决，尽管随后我遇到了关于django.db.utils.integrityyror:core_team.blahblah_id可能不为NULL的问题，我决定回滚，做一些稍微简单的事情-以避免重复查找（比赛链接到球队和联赛），我将编写一个管理命令来导入团队

根据我对上一个问题（显然有缺陷）的理解，我做得很好-它使用

get\u或\u create

检查联赛实例，然后根据该实例分配球队。我还双重检查了DB是否是最新的（我正在向南跑，在上次更改方案时做了向前迁移，自那时以来没有任何变化。上次的变化是将两个模型中的名字作为主键（因为每个名字只有一支球队，每个名字只有一个联赛）

最近，我添加了代码，为团队get_或_create部分提供默认值，但收到了相同的错误。我理解错误的原因（我认为），即团队中的外键“league”已经存在于数据库中，并且不能为null插入另一个团队（从），只是不知道如何修复它

管理指挥部：

from django.core.management.base import BaseCommand, CommandError
import csv
import csvImporter
#from core.models import Match
from time import strptime
from datetime import datetime

master_data = open ('/Users/chris/Desktop/AllDataTruncated.csv', 'r') 
data = list(tuple(rec) for rec in csv.reader(master_data, delimiter=','))

from core.models import League, Team

team_list = []
for row in data:

    if row[2] == "HomeTeam":
        print "Continuing"
        continue
    elif row[2] == "":
        print "Continuing"
        continue
    else:
        league, _ = League.objects.get_or_create(name=row[0])
        print league
        team, _ = Team.objects.get_or_create(team_name=row[2], defaults={'league':league})
        current_team = Team(league = league, team_name=team)

    print current_team 

以及models.py的相关位：

class League (models.Model):
    name = models.CharField(max_length=2, primary_key=True)
    last_modified = models.CharField(max_length=50)
    def __unicode__(self):
        return unicode(self.name)

class Team(models.Model):
    team_name = models.CharField(max_length=50, primary_key=True)
    league = models.ForeignKey(League)
    team_colour = models.CharField(max_length=6, null=True, blank=True)
    def __unicode__(self):
        return unicode (self.team_name)

完整回溯是：

$ python manage.py importteams
Continuing
E0
Traceback (most recent call last):
  File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/__init__.py", line 453, in execute_from_command_line
    utility.execute()
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/__init__.py", line 392, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/__init__.py", line 272, in fetch_command
    klass = load_command_class(app_name, subcommand)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/__init__.py", line 77, in load_command_class
    module = import_module('%s.management.commands.%s' % (app_name, name))
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/utils/importlib.py", line 35, in import_module
    __import__(name)
  File "/Users/chris/Dropbox/Django/gmblnew/core/management/commands/importteams.py", line 26, in <module>
    team2, _ = Team.objects.get_or_create(team_name=row[3])
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/manager.py", line 146, in get_or_create
    return self.get_query_set().get_or_create(**kwargs)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/query.py", line 487, in get_or_create
    six.reraise(*exc_info)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/query.py", line 477, in get_or_create
    obj.save(force_insert=True, using=self.db)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/base.py", line 546, in save
    force_update=force_update, update_fields=update_fields)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/base.py", line 650, in save_base
    result = manager._insert([self], fields=fields, return_id=update_pk, using=using, raw=raw)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/manager.py", line 215, in _insert
    return insert_query(self.model, objs, fields, **kwargs)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/query.py", line 1661, in insert_query
    return query.get_compiler(using=using).execute_sql(return_id)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 937, in execute_sql
    cursor.execute(sql, params)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/backends/util.py", line 41, in execute
    return self.cursor.execute(sql, params)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/backends/sqlite3/base.py", line 364, in execute
    six.reraise(utils.IntegrityError, utils.IntegrityError(*tuple(e.args)), sys.exc_info()[2])
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/db/backends/sqlite3/base.py", line 362, in execute
    return Database.Cursor.execute(self, query, params)
django.db.utils.IntegrityError: core_team.league_id may not be NULL

这就是使这个问题长期存在的原因吗

---

编辑：似乎没有。删除了数据库并移动了South migrations文件夹，它仍然在这样做。源CSV也很好（没有空行或空字符串/段），上面的代码有一个部分可以跳过这些部分；它不会走得太远。

呃。对于任何其他后来的新手来说，这个问题的答案其实非常简单。我在这里做的是在表“Team”中创建一个条目，它有一个返回到“League”的外键

“诀窍”（这不是一个诀窍，只是在文档中解释得很糟糕，imho）是当你为团队对象创建get_或_时，你需要显式地将联盟传递回去。这不仅仅是匹配团队名称

我以为我已经做到了，但似乎我没有做到。这段代码可以工作（并且非常有效地确保没有重复项）：

---

你能放下你的数据库再试一次吗？这样做了，然后从一个完全空白的数据库开始（运行

syncdb

然后

migrate

。migrate提供了…

运行核心迁移：-迁移到0005\u auto\u del\u field\u team\u id\u chg\u field\u team\u team\u name\u add\u unique\u team\u tea.>核心：0001\u initial>core:0002\u auto\u chg\u field\u match\u客场\u目标上的投篮\u chg\u field\u match\u全场比赛\u全场比赛\u全场比赛\u全场比赛ay_shots_on_target____chg_field_match_full_time_

运行importItems之后会出现相同的错误：

django.db.utils.IntegrityError:core_team.league_id可能不为空

这就是我，呃，“强烈不喜欢”的原因南方：迁移地狱。如果您的所有数据都是CSV格式，并且有一个导入程序可以使用：将您的

迁移

目录移动到

/tmp

或其他位置，从一个新的数据库开始，然后再试一次。如果修复了，请用fire杀死迁移目录。好的，尝试了，没有成功，同样的错误。值得注意的是-当我运行它时在空白数据库上，它正确地创建了一个新的联盟对象-在运行impportteams后，E0现在就在那里，在我尝试将一个团队分配给数据库时，它只是出错了。您的文件中是否有任何空行，或者

行[0]

是

'

的任何行？

 ? The field 'League.id' does not have a default specified, yet is NOT NULL.
 ? Since you are removing this field, you MUST specify a default
 ? value to use for existing rows. Would you like to:
 ?  1. Quit now.
 ?  2. Specify a one-off value to use for existing columns now
 ?  3. Disable the backwards migration by raising an exception; you can edit the migration to fix it later
 ? Please select a choice: 3

for row in data:

    if row[2] == "HomeTeam":
        print "Continuing"
        continue
    elif row[2] == "":
        print "Continuing"
        continue
    else:
        league, _ = League.objects.get_or_create(name=row[0])
        print league
        team, _ = Team.objects.get_or_create(team_name=row[2], league=league)
        current_team = Team(league = league, team_name=team)
    print current_team