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Can a foreign key be NULL and/or duplicate?
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Short answer: Yes, it can be NULL or duplicate.
I want to explain why a foreign key might need to be null or might need to be unique or not unique. First remember a Foreign key simply requires that the value in that field must exist first in a...
Ukkonen's suffix tree algorithm in plain English
I feel a bit thick at this point. I've spent days trying to fully wrap my head around suffix tree construction, but because I don't have a mathematical background, many of the explanations elude me as they start to make excessive use of mathematical symbology. The closest to a good explanation that ...
What's wrong with nullable columns in composite primary keys?
ORACLE does not permit NULL values in any of the columns that comprise a primary key. It appears that the same is true of most other "enterprise-level" systems.
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How to disable scrolling temporarily?
I'm using the scrollTo jQuery plugin and would like to know if it is somehow possible to temporarily disable scrolling on the window element through Javascript? The reason I'd like to disable scrolling is that when you scroll while scrollTo is animating, it gets really ugly ;)
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Error handling in Bash
What is your favorite method to handle errors in Bash?
The best example of handling errors I have found on the web was written by William Shotts, Jr at http://www.linuxcommand.org .
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How do you use bcrypt for hashing passwords in PHP?
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bcrypt is a hashing algorithm which is scalable with hardware (via a configurable number of rounds). Its slowness and multiple rounds ensures that an attacker must deploy massive funds and hardware to be able to crack your passwords. Add to that per-...
Wireshark localhost traffic capture [closed]
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If you're using Windows it's not possible - read below. You can use the local address of your machine instead and then you'll be able to capture stuff. See CaptureSetup/Loopback.
Summary: you can capture on the
loopback interface on Linux, on
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How to explicitly discard an out argument?
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Starting with C# 7.0, it is possible to avoid predeclaring out parameters as well as ignoring them.
public void PrintCoordinates(Point p)
{
p.GetCoordinates(out int x, out int y);
WriteLine($"({x}, {y})");
}
public void Print...
Creating a blurring overlay view
...sic app of the new iOS, we can see an album cover behind a view that blurs it.
25 Answers
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Can every recursion be converted into iteration?
A reddit thread brought up an apparently interesting question:
17 Answers
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