大约有 40,000 项符合查询结果（耗时：0.0535秒） [XML]
Rails :dependent => :destroy VS :dependent => :delete_all
...s associated elements where delete_all can delete multiple data from self table as DELETE * FROM table where field = 'xyz'
:Dependent possible options:
Controls what happens to the associated objects when their owner is destroyed. Note that these are implemented as callbacks, and Rails executes ...
How do I see active SQL Server connections?
...ys.sysprocesses WHERE dbid > 0
--Available connections
DECLARE @SPWHO1 TABLE (DBName VARCHAR(1000) NULL, NoOfAvailableConnections VARCHAR(1000) NULL, LoginName VARCHAR(1000) NULL)
INSERT INTO @SPWHO1
SELECT db_name(dbid), count(dbid), loginame FROM sys.sysprocesses WHERE dbid > 0 GROUP B...
CSS @media print issues with background-color;
...and we have a product that uses miles of css. I'm attempting to make a printable stylesheet for our app but I'm having issues with background-color in @media print .
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Why are regular expressions so controversial? [closed]
... just slow, but the performance of the regex engine can be totally unpredictable when faced with arbitrary (user-supplied) inputs.
– Pacerier
Dec 1 '15 at 21:53
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Assertion failure in dequeueReusableCellWithIdentifier:forIndexPath:
...u need to use the dequeueReusableCellWithIdentifier: for that behavior:
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
Notice that dequeueReusableCellWithIdentifier: and dequeueReusableCellWithIdentifier:forIndexPath: are different methods. See doc for the f...
IntelliJ IDEA with Junit 4.7 “!!! JUnit version 3.8 or later expected:”
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Another way: Edit your jdk.table.xml at ~/Library/Preferences/AndroidStudioX.X/options/jdk.table.xml or C:\Users\Name\.AndroidStudioX.X\config\options\jdk.table.xml on Windows. Find the node <name value="Android API 28 Platform" /> and set its &l...
Get second child using jQuery
...As in $(t).find('td').eq(1) to get the second <td>, if t was, say, a table and I needed to look down more than 1 node?
– Justin L.
Sep 8 '16 at 1:05
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How to understand Locality Sensitive Hashing?
...akes as input a set of documents/images/objects and outputs a kind of Hash Table.
The indexes of this table contain the documents such that documents that are on the same index are considered similar and those on different indexes are "dissimilar".
Where similar depends on the metric system and ...
How do I perform an IF…THEN in an SQL SELECT?
...LSE <returndefaultcase>
END AS <newcolumnname>
FROM <table>
The extended case:
SELECT CASE WHEN <test> THEN <returnvalue>
WHEN <othertest> THEN <returnthis>
ELSE <returndefaultcase>
END AS ...
Reference alias (calculated in SELECT) in WHERE clause
... @AaronBertrand - Is your first query a subquery or a derived table ? I don't know the difference between the two even after some quick googling.
– MasterJoe
Sep 4 at 19:57
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