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What is Virtual DOM?
...t. It contains all the details needed to construct the DOM, but because it doesn't require all the heavyweight parts that go into a real DOM, it can be created and changed much more easily.
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Use email address as primary key?
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String comparison is slower than int comparison. However, this does not matter if you simply retrieve a user from the database using the e-mail address. It does matter if you have complex queries with multiple joins.
If you store information about users in multiple tables, the foreign k...
What does FrameLayout do?
...arched, but I couldn't find something useful. What is FrameLayout and what does it do?
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Convert PDF to clean SVG? [closed]
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Inkscape doesn't work too well, as it changes the text into paths, too. I also find that they often lose the font data, but don't seem to approximate a good, installed font. How does PDF display it if SVG can't?
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NSUserDefaults - How to tell if a key exists
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objectForKey: will return nil if it doesn't exist.
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Why does GCC generate 15-20% faster code if I optimize for size instead of speed?
...oice in this particular case and on my machine. Clang 3.4 (trunk) with -O3 does the appropriate alignment and the generated code does not show this weird behavior.
Of course, if an inappropriate alignment is done, it makes things worse. An unnecessary / bad alignment just eats up bytes for no reaso...
How to replace ${} placeholders in a text file?
...ymbol, you would have to escape it with a backslash (otherwise replacement does not occur).
– MatthieuP
Jan 10 '09 at 2:35
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Difference between Pig and Hive? Why have both? [closed]
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Alan also does an article discussing Hive specifically, as shared j03m below. Good stuff from him!
– Dolan Antenucci
Jun 7 '12 at 14:18
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What is the difference between varchar and varchar2 in Oracle?
...en NULL and empty string in future, as ANSI standard prescribes.
VARCHAR2 does not distinguish between a NULL and empty string, and never will.
If you rely on empty string and NULL being the same thing, you should use VARCHAR2.
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What Does Question Mark Mean in Xcode Project Navigator?
...you know is tracked, and the Source Control->Refresh Status menu option doesn't change anything, try just quitting and restarting Xcode. Sigh.
– Matt Gibson
Jan 14 '15 at 20:30
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