大约有 46,000 项符合查询结果（耗时：0.0587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...
Express next function, what is it really for?
...cumentation it says that next('route') can be used to jump to that route and skip all routes in between, but sometimes next is called without arguments. Anybody knows of a good tutorial etc that describes the next function?
...
What are all the uses of an underscore in Scala?
I've taken a look at the list of surveys taken on scala-lang.org and noticed a curious question: " Can you name all the uses of “_”? ". Can you? If yes, please do so here. Explanatory examples are appreciated.
...
Find number of months between two Dates in Ruby on Rails
...is solution does not consider days. The number of months between 28/4/2000 and 1/5/2000 is not 1 month, but 0.
– dgilperez
Aug 19 '13 at 18:39
15
...
How to create ls in windows command prompt?
I want to use ls in windows command prompt and make it run the dir command.
18 Answers
...
Hash Map in Python
... The second example just builds a dict in the same ways as before and then copies it. The other use dict, which would be more appopriate in this context, is dict(key1=value1, key2=value2, ...) but that requires the keys to strings which are also valid Python identifiers (and internally, thi...
Set value of textarea in jQuery
... val does take the time to make sure the value you're setting is a string, and attr seems to do a bit more magic overall.
– enobrev
Jan 6 '09 at 6:31
63
...
Find the last element of an array while using a foreach loop in PHP
...
$numItems = count($arr) trick is not needed and reduces readability - in PHP there is no performance penalty for accessing count($arr) each time. The reason is that items count is internally saved as special field in the array header and is not calculated on-the-fly. T...
How to extract numbers from a string in Python?
...his is better than the regex example because you don't need another module and it's more readable because you don't need to parse (and learn) the regex mini-language.
This will not recognize floats, negative integers, or integers in hexadecimal format. If you can't accept these limitations, jmnas's...
How can I have grep not print out 'No such file or directory' errors?
I'm grepping through a large pile of code managed by git, and whenever I do a grep, I see piles and piles of messages of the form:
...