python – 定义多个模型之间的关系 – Django
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我在三个Django模型之间有以下关系:
class TestCase(models.Model):
'''
Define the testcase model. A testcase is a python Class
which contains a set of tests
'''
name = models.BinaryField(blank=False)
filename = models.BinaryField(blank=True)
run_flag = models.IntegerField(default=0)
run_as_root = models.BooleanField(default=0)
num_tests = models.IntegerField(default=0)
testsuite = models.ForeignKey(TestSuite)
def __str__(self):
return self.name
请忽略TestSuite:这对于这个问题并不重要.每个TestCase都是您可能想象的:TestCase(类).因此,每次执行一个TestCase时,它都有一个TestExecution和一个Result:
class Result(models.Model):
'''
Define the result of a testcase. It may be 'PASS', 'FAIL',
'SKIPPED' or 'ABORTED'
'''
FAIL = 0
PASS = 1
ABORTED = 2
SKIPPED = 3
Status = (
(PASS, 'PASS'),
(FAIL, 'FAIL'),
(SKIPPED, 'SKIPPED'),
(ABORTED, 'ABORTED'),
)
status = models.IntegerField(choices=Status, default=FAIL)
testcase = models.ForeignKey(TestCase)
class TestExecution(models.Model):
name = models.BinaryField(blank=False)
num_testsuites = models.IntegerField(default=0)
time = models.FloatField()
date = models.DateTimeField(default=django.utils.timezone.now)
result = models.OneToOneField(Result)
def __str__(self):
return self.name + " : " + self.date + " : " + self.time
可以这么说,TestCase有很多结果,但Result和TestExecution之间的关系是OneToOne.我的模型架构遇到了一些问题.我知道一个简单的解决方案是合并表Result和TestExecution:
python manage.py migrate
Operations to perform:
Synchronize unmigrated apps: staticfiles, messages
Apply all migrations: admin, autotester, contenttypes, auth, sessions
Synchronizing apps without migrations:
Creating tables...
Running deferred SQL...
Installing custom SQL...
Running migrations:
Rendering model states... DONE
Applying autotester.0005_auto_20150519_1831...Traceback (most recent call last):
File "manage.py", line 10, in <module>
execute_from_command_line(sys.argv)
File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 338, in execute_from_command_line
utility.execute()
File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 330, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 390, in run_from_argv
self.execute(*args, **cmd_options)
File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 441, in execute
output = self.handle(*args, **options)
File "/usr/local/lib/python2.7/dist-packages/django/core/management/commands/migrate.py", line 221, in handle
executor.migrate(targets, plan, fake=fake, fake_initial=fake_initial)
File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/executor.py", line 110, in migrate
self.apply_migration(states[migration], migration, fake=fake, fake_initial=fake_initial)
File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/executor.py", line 147, in apply_migration
state = migration.apply(state, schema_editor)
File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/migration.py", line 115, in apply
operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/operations/fields.py", line 62, in database_forwards
field,
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/mysql/schema.py", line 43, in add_field
super(DatabaseSchemaEditor, self).add_field(model, field)
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/base/schema.py", line 403, in add_field
self.execute(sql, params)
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/base/schema.py", line 111, in execute
cursor.execute(sql, params)
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/utils.py", line 79, in execute
return super(CursorDebugWrapper, self).execute(sql, params)
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/utils.py", line 64, in execute
return self.cursor.execute(sql, params)
File "/usr/local/lib/python2.7/dist-packages/django/db/utils.py", line 97, in __exit__
six.reraise(dj_exc_type, dj_exc_value, traceback)
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/utils.py", line 64, in execute
return self.cursor.execute(sql, params)
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/mysql/base.py", line 124, in execute
return self.cursor.execute(query, args)
File "/usr/local/lib/python2.7/dist-packages/MySQLdb/cursors.py", line 205, in execute
self.errorhandler(self, exc, value)
File "/usr/local/lib/python2.7/dist-packages/MySQLdb/connections.py", line 36, in defaulterrorhandler
raise errorclass, errorvalue
django.db.utils.IntegrityError: (1062, "Duplicate entry '0' for key 'result_id'")
关于模型架构,最合适的方法是什么?
根据请求添加autotester / migrations / 0005_auto_20150519_1831.py:
# – 编码:utf-8 –
来自未来的导入unicode_literals
来自django.db导入模型,迁移
class Migration(migrations.Migration):
dependencies = [
('autotester', '0004_auto_20150519_1744'),
]
operations = [
migrations.RemoveField(
model_name='testexecution',
name='framework',
),
migrations.AddField(
model_name='testexecution',
name='result',
field=models.OneToOneField(default=None, to='autotester.Result'),
preserve_default=False,
),
]
解决方法:
OneToOneField类似于ForeignKey,其唯一值= True.
如果您的数据库不为空,则无法添加具有唯一约束的字段,因此您会遇到此问题.你要做的是:
>添加没有唯一约束的字段= ForeignKey
>填写此字段,了解您将拥有的即将到来的唯一约束
>将ForeignKey更改为OneToOneField
以下是详细步骤:
第一步:
删除autotester / migrations / 0005_auto_20150519_1831.py文件,并在TestExecution模型中使用result = models.ForeignKey(Result,null = True,blank = True)更改结果字段并执行迁移:
./manage.py makemigrations autotester
./manage.py migrate autotester
第二步:
对于您拥有的每个结果,创建一个TestExecution(用适当的数据替换FOO):
results = Result.objects.all()
for result in results:
tst = TestExecution()
tst.name = FOO
tst. num_testsuites = FOO
tst.time = FOO
tst.result_id = result.id
tst.save()
第三步
使用result = models.OneToOneField(Result)更改结果字段,然后执行迁移:
./manage.py makemigrations autotester
./manage.py migrate autotester
你应该好好去.
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