[英]Defining relationships across Multiple Models - Django
I have the following relationship between three Django
models: 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
Please ignore TestSuite
: it's not important for this problem. 请忽略TestSuite
:这对于这个问题并不重要。 Every TestCase
is what you may imagine: a TestCase
(class). 每个TestCase
都是您可能想象的: TestCase
(类)。 So every time one executes a TestCase
it has a TestExecution
and a Result
: 因此,每次执行一个TestCase
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
That can be said, a TestCase
hasMany
Result
but the relationship between Result
and TestExecution
is OneToOne
. 可以hasMany
说, TestCase
Result
但Result
和TestExecution
之间的关系是OneToOne
。 I'm having some problems with my models schema. 我的模型架构遇到了一些问题。 I know a simple solution would be to merge
the tables Result
and TestExecution
: 我知道一个简单的解决方案是merge
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'")
What's the most appropriate way to proceed regarding the models schema? 关于模型架构,最合适的方法是什么?
Adding the autotester/migrations/0005_auto_20150519_1831.py
as per request: 根据请求添加autotester/migrations/0005_auto_20150519_1831.py
:
# - - coding: utf-8 - - from future import unicode_literals # - - coding:utf-8 - 来自未来的导入unicode_literals
from django.db import models, migrations 来自django.db导入模型,迁移
class Migration(migrations.Migration): 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,
),
]
A OneToOneField
is a like a ForeignKey
with unique=True
. OneToOneField
类似于ForeignKey
,其unique=True
。
You problem comes with this unique constraint since you can't add a field with a unique constraint if your database is not empty. 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。 What you have to do is: 你要做的是:
ForeignKey
添加没有唯一约束的字段= ForeignKey
OneToOneField
将ForeignKey更改为OneToOneField
Here are the detailed steps: 以下是详细步骤:
First step: 第一步:
Delete your autotester/migrations/0005_auto_20150519_1831.py
file and change your result
field with result = models.ForeignKey(Result, null=True, blank=True)
in your TestExecution
model and do the migration: 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result
字段并执行迁移:
./manage.py makemigrations autotester
./manage.py migrate autotester
Second Step: 第二步:
For every Result
you have, create a TestExecution
(replace FOO with the appropriate datas): 对于您拥有的每个Result
,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()
Third step 第三步
Change your result field with result = models.OneToOneField(Result)
and then do the migration: 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
You should be good to go. 你应该好好去。
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