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Can a foreign key be NULL and/or duplicate?
...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 different table (the parent table). That is all an FK is by d...
What is the use of “ref” for reference-type variables in C#?
...ass a value-type ( int , struct , etc.) as a parameter (without the ref keyword), a copy of that variable is passed to the method, but if I use the ref keyword a reference to that variable is passed, not a new one.
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Show just the current branch in Git
I tried looking for a special Git command for this, but I couldn't find one. Is there anything shorter or faster than the following?
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How do I remove documents using Node.js Mongoose?
The above doesn't seem to work. The records are still there.
22 Answers
22
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C# List of objects, how do I get the sum of a property
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Alex LEAlex LE
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Changes in import statement python3
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Relative import happens whenever you are importing a package relative to the current script/package.
Consider the following tree for example:
mypkg
├── base.py
└── derived.py
Now, your derived.py requires something from base.py. In Python 2, you could do it like th...
Use of 'use utf8;' gives me 'Wide character in print'
..., map { ord } split //, "鸡\n";'
233:184:161:10
The first three bytes make up your character, the last one is the line-feed.
The call to print sends these four characters to STDOUT. Your console then works out how to display these characters. If your console is set to use UTF8, then it will inte...
What’s the best way to check if a file exists in C++? (cross platform)
I have read the answers for What's the best way to check if a file exists in C? (cross platform) , but I'm wondering if there is a better way to do this using standard c++ libs? Preferably without trying to open the file at all.
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How can I get the browser's scrollbar sizes?
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From Alexandre Gomes Blog I have not tried it. Let me know if it works for you.
function getScrollBarWidth () {
var inner = document.createElement('p');
inner.style.width = "100%";
inner.style.height = "200px";
var outer = document.createElement('div');
outer.style.p...
jquery save json data object in cookie
How do I save JSON data in a cookie?
6 Answers
6
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