大约有 42,000 项符合查询结果（耗时：0.0721秒） [XML]
Are foreign keys really necessary in a database design?
... ON DELETE CASCADE. This means that if you have one table containing users and another containing orders or something, then deleting a user could automatically delete all orders that point to that user.
share
|
...
Regex Email validation
...
TLD's like .museum aren't matched this way, and there are a few other long TLD's. Also, you can validate email addresses using the MailAddress class as Microsoft explains here in a note:
Instead of using a regular expression to validate an email address,
you can ...
How do I raise the same Exception with a custom message in Python?
...thon 3, check Ben's answer
To attach a message to the current exception and re-raise it:
(the outer try/except is just to show the effect)
For python 2.x where x>=6:
try:
try:
raise ValueError # something bad...
except ValueError as err:
err.message=err.message+" hello"
...
Share data between AngularJS controllers
... in multiple display locations outside the original controller. Code below and in jsfiddle here .
10 Answers
...
Getting vertical gridlines to appear in line plot in matplotlib
I want to get both horizontal and vertical grid lines on my plot but only the horizontal grid lines are appearing by default. I am using a pandas.DataFrame from an sql query in python to generate a line plot with dates on the x-axis. I'm not sure why they do not appear on the dates and I have trie...
Putting git hooks into repository
... A great way around this is to drop in a hook wrapper script in your repo, and symlink all of the hooks to it. The wrapper can then examine $0 (assuming it's a bash script; an equivalent like argv[0] otherwise) to figure out which hook it was invoked as, then invoke the appropriate hook within your ...
Fixed width buttons with Bootstrap
...otstrap support fixed width buttons? Currently if I have 2 buttons, "Save" and "Download", the button size changes based on content.
...
How to do multiple arguments to map function where one remains the same in python?
...ally is an issue for you, the speed difference between list comprehensions and map() won't help either way.
– Sven Marnach
May 31 '12 at 13:54
...
Writing to output window of Visual Studio
...e Java's system.out.println("") . I tried Debug.Write , Console.Write , and Trace.Write . It does not give an error, but it does not print anything either.
...
SQL Server - When to use Clustered vs non-Clustered Index?
I know primary differences between clustered and non clustered indexes and have an understanding of how they actually work. I understand how clustered and non-clustered indexes improve read performance. But one thing I am not sure is that what would be the reasons where I would choose one over the o...