大约有 30,000 项符合查询结果（耗时：0.0413秒） [XML]
Sequence contains no matching element
...hrowing the exception:
var documentRow = _dsACL.Documents.First(o => o.ID == id)
First() will throw an exception if it can't find any matching elements. Given that you're testing for null immediately afterwards, it sounds like you want FirstOrDefault(), which returns the default value for the ...
Database Design for Tagging
...ke it will suit the situation well. However, I'm not convinced it's a good idea to implement bitmap indexing "manually", like digiguru suggests: It sounds like a complicated situation whenever new tags are added(?) But some DBMSes (including Oracle) offer bitmap indexes which may somehow be of use, ...
How are msys, msys2, and msysgit related to each other?
...(though it does that very well). It has a software building infrastructure called makepkg that allows the creation of recipes (PKGBUILD and patch files) for building software.
IMHO, the adoption of Pacman changes things significantly for open source development on Windows. Instead of everyone hacki...
Insert a row to pandas dataframe
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Not sure how you were calling concat() but it should work as long as both objects are of the same type. Maybe the issue is that you need to cast your second vector to a dataframe? Using the df that you defined the following works for me:
df2 = pd...
Count with IF condition in MySQL query
...unt()
Try below:
SELECT
ccc_news . * ,
SUM(if(ccc_news_comments.id = 'approved', 1, 0)) AS comments
FROM
ccc_news
LEFT JOIN
ccc_news_comments
ON
ccc_news_comments.news_id = ccc_news.news_id
WHERE
`ccc_news`.`category` = 'news_layer2'
AND `ccc_news`.`sta...
Clean way to launch the web browser from shell script?
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If you're going to use npm, there's a package called open, but it's still overkill
– Matt Fletcher
Aug 16 '17 at 16:14
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How to get the Full file path from URI
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Use:
String path = yourAndroidURI.uri.getPath() // "/mnt/sdcard/FileName.mp3"
File file = new File(new URI(path));
or
String path = yourAndroidURI.uri.toString() // "file:///mnt/sdcard/FileName.mp3"
File file = new File(new URI(path));
...
What does the keyword Set actually do in VBA?
...ables. By doing a Set I suspect that under the hood it's doing an AddRef() call on the object to manage it's lifetime.
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Can an interface extend multiple interfaces in Java?
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@sureshatta - so what happens? does it call both ??
– Fattie
Dec 8 '16 at 14:51
4
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generate model using user:references vs user_id:integer
..., you can see that this is the case:
:001 > Micropost
=> Micropost(id: integer, user_id: integer, created_at: datetime, updated_at: datetime)
The second command adds a belongs_to :user relationship in your Micropost model whereas the first does not. When this relationship is specified, Ac...