大约有 44,000 项符合查询结果（耗时：0.0874秒） [XML]
Validate uniqueness of multiple columns
Is there a rails-way way to validate that an actual record is unique and not just a column? For example, a friendship model / table should not be able to have multiple identical records like:
...
Is there XNOR (Logical biconditional) operator in C#?
I'm new to C# and could not find XNOR operator to provide this truth table:
4 Answers
...
How can I see the specific value of the sql_mode?
...RACLE,NO_KEY_OPTIONS,NO_TABLE_OPTIONS,NO_FIELD_OPTIONS,NO_AUTO_CREATE_USER and etc are not set? Or do you mean that some of them are set but simply not shown by default?
– Pacerier
Apr 22 '16 at 3:44
...
Change app language programmatically in Android
...ssible to change the language of an app programmatically while still using Android resources?
35 Answers
...
How to easily map c++ enums to strings
I have a bunch of enum types in some library header files that I'm using, and I want to have a way of converting enum values to user strings - and vice-versa.
...
redirect COPY of stdout to log file from within bash script itself
...ptured - i.e. your
# log file would not contain any error messages.
# SEE (and upvote) the answer by Adam Spiers, which keeps STDERR
# as a separate stream - I did not want to steal from him by simply
# adding his answer to mine.
exec 2>&1
echo "foo"
echo "bar" >&2
Note that this is...
Django migration strategy for renaming a model and relationship fields
...ome errors if you don't update the names where it's imported e.g. admin.py and even older migration files (!).
Update: As ceasaro mentions, newer versions of Django are usually able to detect and ask if a model is renamed. So try manage.py makemigrations first and then check the migration file.
...
How to use OpenSSL to encrypt/decrypt files?
I want to crypt and decrypt one file using one password.
10 Answers
10
...
HttpClient.GetAsync(…) never returns when using await/async
... misusing the API.
Here's the situation: in ASP.NET, only one thread can handle a request at a time. You can do some parallel processing if necessary (borrowing additional threads from the thread pool), but only one thread would have the request context (the additional threads do not have the reque...
Immediate Child selector in LESS
...>.control {
...
}
}
Note the lack of space between ">" and ".", otherwise it won't work.
share
|
improve this answer
|
follow
|
...