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Nullable Foreign Key bad practice?
... read.
Only if you know better than Chris Date "what first normal form really means". If x and y are both nullable, and indeed in some row x and y are both null, then WHERE x=y does not yield true. This proves beyond reasonable doubt that null is not a value (because any real value is always equ...
离线版启动超时，有报错日志 - App Inventor 2 离线版 - 清泛IT社区，为创新赋能！
...ources\app.asar.unpacked\OpenJDK\bin\java, --add-opens=java.base/java.lang=ALL-UNNAMED, -Xmx4G, --add-opens, java.base/java.net=ALL-UNNAMED, --add-opens, java.base/sun.net.www.protocol.http=ALL-UNNAMED, --add-opens, java.base/sun.net.www.protocol.https=ALL-UNNAMED, -Dfile.encoding=UTF-8, -classpath,...
ALTER DATABASE failed because a lock could not be placed on database
...ng.
Connection 1 (leave running for a couple of minutes)
CREATE DATABASE TESTING123
GO
USE TESTING123;
SELECT NEWID() AS X INTO FOO
FROM sys.objects s1,sys.objects s2,sys.objects s3,sys.objects s4 ,sys.objects s5 ,sys.objects s6
Connections 2 and 3
set lock_timeout 5;
ALTER DATABASE TESTING1...
Encode URL in JavaScript?
...
I would suggest to use qs npm package
qs.stringify({a:"1=2", b:"Test 1"}); // gets a=1%3D2&b=Test+1
it is easier to use with JS object and it gives you proper URL encoding for all parameters
If you are using jQuery I would go for $.param method. It URL encodes an object mapping field...
Why use a ReentrantLock if one can use synchronized(this)?
...gher contention. You can read more about this here.
This claim has been contested, however; see the following comment:
In the reentrant lock test, a new lock is created each time, thus there is no exclusive locking and the resulting data is invalid. Also, the IBM link offers no source code for the ...
Align image in center and middle within div
...00%; height:100%">
<img src="http://www.garcard.com/images/garcard_symbol.png">
</div>
JSFiddle
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Link and execute external JavaScript file hosted on GitHub
...the linked reference of a local JavaScript file to a GitHub raw version my test file stops working. The error is:
15 Answe...
java.lang.ClassNotFoundException: org.springframework.web.servlet.DispatcherServlet
...upId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>${spring.version}</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifac...
Big O, how do you calculate/approximate it?
... @SamyBencherif: That would be a typical way to check (actually, just testing x & 1 would be sufficient, no need to check == 1; in C, x&1==1 is evaluated as x&(1==1) thanks to operator precedence, so it's actually the same as testing x&1). I think you're misreading the answer th...
Changes in import statement python3
...a single function. In Python 2 you were permitted to be semi-lazy:
def sin_degrees(x):
from math import *
return sin(degrees(x))
Note that it already triggers a warning in Python 2:
a.py:1: SyntaxWarning: import * only allowed at module level
def sin_degrees(x):
In modern Python 2 co...