大约有 47,000 项符合查询结果（耗时：0.0893秒） [XML]
What's wrong with nullable columns in composite primary keys?
...keys is not clean relational database design.
If there are two entities A and B where A can optionally be related to B, the clean solution is to create a resolution table (let's say AB). That table would link A with B: If there is a relationship then it would contain a record, if there isn't then i...
INSERT IF NOT EXISTS ELSE UPDATE?
... the ID column: In the replacement case the statement would set it to NULL and then a fresh ID would be allocated.
This approach can also be used if you want to leave particular field values alone if the row in the replacement case but set the field to NULL in the insert case.
For example, assumin...
WatiN or Selenium? [closed]
... tests of our presentation soon. It seems that everyone recommends WatiN and Selenium . Which do you prefer for automated testing of ASP.NET web forms? Which of these products work better for you?
...
Regex: Specify “space or start of string” and “space or end of string”
...
You can use any of the following:
\b #A word break and will work for both spaces and end of lines.
(^|\s) #the | means or. () is a capturing group.
/\b(stackoverflow)\b/
Also, if you don't want to include the space in your match, you can use lookbehind/aheads.
(?<=\...
Django filter versus get for single object?
...lly implemented in Django, so there should be no "performance" difference (and the fact that you're thinking about it indicates you're violating one of the cardinal rules of programming, namely trying to optimize code before it's even been written and profiled -- until you have the code and can run ...
Alternatives to gprof [closed]
...used in the presence of mutual recursion. But the visualizer is very nice and light years ahead of gprof.
share
|
improve this answer
|
follow
|
...
Is there a standard sign function (signum, sgn) in C/C++?
I want a function that returns -1 for negative numbers and +1 for positive numbers.
http://en.wikipedia.org/wiki/Sign_function
It's easy enough to write my own, but it seems like something that ought to be in a standard library somewhere.
...
How to install Android SDK Build Tools on the command line?
I want to setup the Android dev environment from command line, and encounter the following issue:
19 Answers
...
Rails find_or_create_by more than one attribute?
There is a handy dynamic attribute in active-record called find_or_create_by:
5 Answers
...
how to log in to mysql and query the database from linux terminal
...om linux terminal?
It depends. Red Hat based distros have the service command:
service mysqld stop
Other distros require to call the init script directly:
/etc/init.d/mysqld stop
3. How I start the mysql server from linux terminal?
Same as #2, but with start.
4. How do I get mysql prompt in...