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Geek981108V2EX 第 508441 号会员，加入于 2020-09-16 22:01:14 +08:00 |
| 出一台最后一代 Intel MBP 16 2.4G i9 64G 1T 5500M 8G 二手交易 • Geek981108 • 2022-09-06 12:22:16 PM |
Geek981108 最近回复了
2022-09-06 12:19:47 +08:00 回复了 tbg 创建的主题 › MacBook Pro › MacBook Pro 2019 16 寸能卖多少了？大佬估个价 |
相同配置, 现在挂着 1.43 待售
2021-05-20 09:32:11 +08:00 回复了 ETONG 创建的主题 › Ubuntu › ubuntu 用 smb 挂载 truenas 的文件夹，挂载完之后文件夹上面有一个小锁的标志，只有管理员能写入和修改文件，这是咋回事。我在 truenas 里面已经分配了任何人都可以写入的权限了，并且 Mac os 测试可以正常读写 |
@ETONG 不行，直接设置 smb 的挂载权限 和 chmod 不太一样，在挂载时候指定就好了
2021-05-18 22:28:49 +08:00 回复了 ETONG 创建的主题 › Ubuntu › ubuntu 用 smb 挂载 truenas 的文件夹，挂载完之后文件夹上面有一个小锁的标志，只有管理员能写入和修改文件，这是咋回事。我在 truenas 里面已经分配了任何人都可以写入的权限了，并且 Mac os 测试可以正常读写 |
mount -t cifs -o vers=3,rw,dir_mode=0777,file_mode=0777,username=xxx,password=xxx //10.0.1.1/xuyihe/xuyihe /xxx
把 xxx 换成自己的路径，指定没问题，同 truenas + ubuntu
把 xxx 换成自己的路径，指定没问题，同 truenas + ubuntu
2021-01-26 20:07:29 +08:00 回复了 Phishion 创建的主题 › Django › Django 更新一条可能不存在的特定数据是 Get 性能好还是 Filter 好 |
文档如是说：
update_or_create()
update_or_create(defaults=None, **kwargs)
A convenience method for updating an object with the given kwargs, creating a new one if necessary. The defaults is a dictionary of (field, value) pairs used to update the object. The values in defaults can be callables.
Returns a tuple of (object, created), where object is the created or updated object and created is a boolean specifying whether a new object was created.
The update_or_create method tries to fetch an object from database based on the given kwargs. If a match is found, it updates the fields passed in the defaults dictionary.
This is meant as a shortcut to boilerplatish code. For example:
defaults = {'first_name': 'Bob'}
try:
obj = Person.objects.get(first_name='John', last_name='Lennon')
for key, value in defaults.items():
setattr(obj, key, value)
obj.save()
except Person.DoesNotExist:
new_values = {'first_name': 'John', 'last_name': 'Lennon'}
new_values.update(defaults)
obj = Person(**new_values)
obj.save()
This pattern gets quite unwieldy as the number of fields in a model goes up. The above example can be rewritten using update_or_create() like so:
obj, created = Person.objects.update_or_create(
first_name='John', last_name='Lennon',
defaults={'first_name': 'Bob'},
)
For detailed description how names passed in kwargs are resolved see get_or_create().
As described above in get_or_create(), this method is prone to a race-condition which can result in multiple rows being inserted simultaneously if uniqueness is not enforced at the database level.
Like get_or_create() and create(), if you’re using manually specified primary keys and an object needs to be created but the key already exists in the database, an IntegrityError is raised.
update_or_create()
update_or_create(defaults=None, **kwargs)
A convenience method for updating an object with the given kwargs, creating a new one if necessary. The defaults is a dictionary of (field, value) pairs used to update the object. The values in defaults can be callables.
Returns a tuple of (object, created), where object is the created or updated object and created is a boolean specifying whether a new object was created.
The update_or_create method tries to fetch an object from database based on the given kwargs. If a match is found, it updates the fields passed in the defaults dictionary.
This is meant as a shortcut to boilerplatish code. For example:
defaults = {'first_name': 'Bob'}
try:
obj = Person.objects.get(first_name='John', last_name='Lennon')
for key, value in defaults.items():
setattr(obj, key, value)
obj.save()
except Person.DoesNotExist:
new_values = {'first_name': 'John', 'last_name': 'Lennon'}
new_values.update(defaults)
obj = Person(**new_values)
obj.save()
This pattern gets quite unwieldy as the number of fields in a model goes up. The above example can be rewritten using update_or_create() like so:
obj, created = Person.objects.update_or_create(
first_name='John', last_name='Lennon',
defaults={'first_name': 'Bob'},
)
For detailed description how names passed in kwargs are resolved see get_or_create().
As described above in get_or_create(), this method is prone to a race-condition which can result in multiple rows being inserted simultaneously if uniqueness is not enforced at the database level.
Like get_or_create() and create(), if you’re using manually specified primary keys and an object needs to be created but the key already exists in the database, an IntegrityError is raised.
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