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Difference between Key, Primary Key, Unique Key and Index in MySQL
...would use indexes to improve the speed of data retrieval. An index is typically created on columns used in JOIN, WHERE, and ORDER BY clauses.
Imagine you have a table called users and you want to search for all the users which have the last name 'Smith'. Without an index, the database would have t...
How to impose maxlength on textArea in HTML using JavaScript
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@JoshStodola - Indeed you cannot. It would really annoy me as a user if I had pasted a whole piece of something in a textarea, clicked submit, and only saw a small portion of it go through without any response.
– Travis J
Apr 30 '1...
isset() and empty() - what to use
... check - is variable empty or contains something. To solve this task, I usually do the following.
6 Answers
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Working with time DURATION, not time of day
... cell B2 and drag as far down as the A column goes to apply the formula to all data in col A.
Last step, be sure to highlight all of column B and set it to Number format (the application of the formula may have automatically set format to Time).
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What is the most frequent concurrency issue you've encountered in Java? [closed]
...are not synchronized this is not guaranteed to work. This mistake is especially devilish as in 99.999% it won't matter in practice as the reader thread will eventually see the change - but we don't know how soon he saw it.
s...
Get MD5 hash of big files in Python
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@Boris, you can't actually say that BLAKE2 is secure. All you can say is that it hasn't been broken yet.
– vy32
Apr 8 at 14:57
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How to recognize USB devices in Virtualbox running on a Linux host? [closed]
...and log in again
Attach to your PC the USB devices you want to be automatically mounted in the VM (virtual machine).
Open Virtualbox
Select your VM and go to "Machine" -> "Settings" -> "USB".
Check "Enable USB Controller"; click on the icon with the USB plug and the plus, and
click on the devi...
Set cursor position on contentEditable
... range.collapse();
range.insertNode(cursorEnd);
}
};
// Add callbacks to afterFocus to be called after cursor is replaced
// if you like, this would be useful for styling buttons and so on
var afterFocus = [];
editable.onfocus = function(e) {
// Slight delay will avoid the initial ...
How to align 3 divs (left/center/right) inside another div?
...div style="clear:both;"></div> which will extend #container vertically to contain both side floats instead of taking its height only from #center and possibly allowing the sides to protrude out the bottom.
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How can I get a list of locally installed Python modules?
I would like to get a list of Python modules, which are in my Python installation (UNIX server).
30 Answers
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