大约有 47,000 项符合查询结果（耗时：0.0878秒） [XML]
How to get execution time in rails console?
I want compare time of execution Post.all and SELECT * FROM posts (or some other statements) How can i get execution time of Post.all ?
...
Should an Enum start with a 0 or a 1?
...nes:
✔️ DO provide a value of zero on simple enums.
Consider calling the value something like "None." If such a value is not appropriate for this particular enum, the most common default value for the enum should be assigned the underlying value of zero.
Framework Design Guidelines / ...
In MySQL queries, why use join instead of where?
...le about using strict typing whenever possible. Explicit is almost universally better.
Conclusion
Short of familiarity and/or comfort, I don't see any benefit to continuing to use the ANSI-89 WHERE clause instead of the ANSI-92 JOIN syntax. Some might complain that ANSI-92 syntax is more verb...
Why does typeof array with objects return “object” and not “array”? [duplicate]
...data);
But the most reliable way is:
isArr = Object.prototype.toString.call(data) == '[object Array]';
Since you tagged your question with jQuery, you can use jQuery isArray function:
var isArr = $.isArray(data);
shar...
MySQL复制的概述、安装、故障、技巧、工具 - 数据库(内核) - 清泛网 - 专注...
...MyISAM表类型的话，可按如下方式操作：
shell> mysqldump --all-databases --master-data=1 > data.sql
注：master-data选项缺省会打开lock-all-tables，并写入CHANGE MASTER TO语句。
如果数据库使用的是InnoDB表类型的话，则应该使用single-transcation：
s...
Can git be integrated with Xcode?
...
NOTE: despite all the up-votes, this answer is out of date as of June 2010
There's no git support within Xcode, but that's no reason not to use git for your Xcode projects. I've had good results managing my Xcode projects using the stan...
What are some better ways to avoid the do-while(0); hack in C++?
...ate these decisions in a function and use returns instead of breaks. While all these checks correspond to the same level of abstraction as of the function, it is quite logical approach.
For example:
void foo(...)
{
if (!condition)
{
return;
}
...
if (!other condition)
{
...
Correct way to detach from a container without stopping it
...aseimage-docker/#intro)
If you want a container that run in detached mode all the time, i suggest you use
docker run -d foo
With an ssh server on the container. (easiest way is to follow the dockerizing openssh tutorial https://docs.docker.com/engine/examples/running_ssh_service/)
Or you can ju...
How accurately should I store latitude and longitude?
...
Actually, equator is best case. One latitude and one longitude degree are the same size at the equator (69 miles), but one degree of longitude shrinks to zero as it approaches either of the poles. Here's a very nice explanation: ...
What is more efficient: Dictionary TryGetValue or ContainsKey+Item?
...ll be faster.
ContainsKey uses the same check as TryGetValue, which internally refers to the actual entry location. The Item property actually has nearly identical code functionality as TryGetValue, except that it will throw an exception instead of returning false.
Using ContainsKey followed by t...