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Can a foreign key be NULL and/or duplicate?
...at field must exist first in a different table (the parent table). That is all an FK is by definition. Null by definition is not a value. Null means that we do not yet know what the value is.
Let me give you a real life example. Suppose you have a database that stores sales proposals. Suppose furth...
Object.getOwnPropertyNames vs Object.keys
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There is a little difference. Object.getOwnPropertyNames(a) returns all own properties of the object a. Object.keys(a) returns all enumerable own properties. It means that if you define your object properties without making some of them enumerable: false these two methods will give you the sa...
dyld: Library not loaded … Reason: Image not found
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Find all the boost libraries:
$ otool -L exefile
exefile:
@executable_path/libboost_something.dylib (compatibility version 0.7.0, current version 0.7.0)
/usr/lib/libc++.1.dylib (compatibility version 1.0.0, curren...
How do I drag and drop files into an application?
...orm1 : Form {
public Form1() {
InitializeComponent();
this.AllowDrop = true;
this.DragEnter += new DragEventHandler(Form1_DragEnter);
this.DragDrop += new DragEventHandler(Form1_DragDrop);
}
void Form1_DragEnter(object sender, DragEventArgs e) {
if (e.Data....
Resuming git-svn clone
...t and slept on me. Is there a way to resume the operation without redoing all of the initial work?
4 Answers
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How to remove a file from version control without deleting it?
...ory. In the event you wish to remove files from the repo, BUT keep them locally on your machine then you'd use the flag above.
– Greg Hilston
Feb 22 '16 at 13:31
6
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SVN (Subversion) Problem “File is scheduled for addition, but is missing” - Using Versions
...p into the cold water and fire up your hidden Mac command shell :-) (it's called "Terminal" in the german OSX, no idea how to bring it up in the english version...)
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Replacing H1 text with a logo image: best method for SEO and accessibility?
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For all who are wondering what's in the linked video: Matt Cutts basically says, you should use the alt attribute of the img tag instead of hiding text with css.
– bjunix
Nov 21 '16 at 15:39...
Difference between
...ts, what type of object could you add to List foo3 that would be legal for all the above possible ArrayList assignments:
You can't add an Integer because foo3 could be pointing at a List<Double>.
You can't add a Double because foo3 could be pointing at a List<Integer>.
You can't add a ...
What's the difference between a single precision and double precision floating point operation?
...as the greater data precision available with 64-bit data types is not typically required by 3D games, as well as the fact that processing 64-bit data uses twice as much RAM, cache, and bandwidth, thereby reducing the overall system performance.
From Webopedia:
The term double precision is some...