大约有 40,000 项符合查询结果（耗时：0.0205秒） [XML]
MySQL: Fastest way to count number of rows
...
When you COUNT(*) it takes in count column indexes, so it will be the best result. Mysql with MyISAM engine actually stores row count, it doensn't count all rows each time you try to count all rows. (based on primary key's column)
Using PHP to count rows is not very ...
Paging with Oracle
...st: 300,110
Old method cost: 30
The new syntax caused a full scan of the index on my column, which was the entire cost. Chances are, things get much worse when limiting on unindexed data.
Let's have a look when including a single unindexed column on the previous dataset:
New method time/cost: ...
How to query MongoDB with “like”?
...
Actually, it depends. If the query doesn't use an index, and must do a table scan, then it can certainly be expensive. If you're doing a 'starts with' regex query, then that can use an index. Best to run an explain() to see what's happening.
– Kyle Bank...
Fastest method to replace all instances of a character in a string [duplicate]
...
Try this replaceAll:
http://dumpsite.com/forum/index.php?topic=4.msg8#msg8
String.prototype.replaceAll = function(str1, str2, ignore)
{
return this.replace(new RegExp(str1.replace(/([\/\,\!\\\^\$\{\}\[\]\(\)\.\*\+\?\|\<\>\-\&])/g,"\\$&"),(ignore?"gi":"...
Deleting all files from a folder using PHP?
...)) {
$scan = glob(rtrim($str,'/').'/*');
foreach($scan as $index=>$path) {
recursiveDelete($path);
}
return @rmdir($str);
}
}
share
|
improve this...
How can I enable auto complete support in Notepad++?
...
Documentation moved yet again: npp-wiki.tuxfamily.org/index.php?title=Auto_Completion - Also, instructions on creating auto-completion files: npp-wiki.tuxfamily.org/…
– AgentRev
Oct 14 '14 at 14:46
...
How to ignore files which are in repository?
... it locally, you could also make it ignored by the git status:
git update-index --assume-unchanged config.php
share
|
improve this answer
|
follow
|
...
How do you make Git ignore files without using .gitignore?
...See also this SO question)
The other two solutions involve updating the index (git update-index):
git update-index --assume-unchanged: see "Git: untrack a file in local repo only and keep it in the remote repo".
It is mentioned by Elijah Lynn in the comments.
You can even ignore a folder co...
How to escape a JSON string to have it in a URL?
...
Using encodeURIComponent():
var url = 'index.php?data='+encodeURIComponent(JSON.stringify({"json":[{"j":"son"}]})),
share
|
improve this answer
|
...
Possibility of duplicate Mongo ObjectId's being generated in two different collections?
... }
> db.foo.insert({_id: 'abc', data:'xyz'})
E11000 duplicate key error index: test.foo.$_id_ dup key: { : "abc" }
So, absolutely don't rely on _id's being unique across collections, and since you don't control the ObjectId generation function, don't rely on it.
It's possible to create somet...