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SQL: How to properly check if a record exists
...rs in recent RDBMS's optimize SELECT COUNT(*) anyway, so while there is a difference in theory (and older databases), you shouldn't notice any difference in practice.
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MySQL ON DUPLICATE KEY - last insert id?
...ression to that MySQL function.
From the MySQL documentation example:
If a table contains an AUTO_INCREMENT column and INSERT ... UPDATE inserts a row, the LAST_INSERT_ID() function returns the AUTO_INCREMENT value. If the statement updates a row instead, LAST_INSERT_ID() is not meaningful. How...
How can I interrupt a ServerSocket accept() method?
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And what to do if the connection was already accepted and the thread is waiting for some data: while((s=in.readLine()) != null) ?
– Alex Fedulov
Aug 24 '12 at 10:56
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Where do you include the jQuery library from? Google JSAPI? CDN?
...th the jsapi method since I don't leverage any other Google API's, however if that ever changed then I would consider it...
First: The Google api servers are distributed across the world instead of my single server location: Closer servers usually means faster response times for the visitor.
Seco...
Iterating through a Collection, avoiding ConcurrentModificationException when removing objects in a
We all know you can't do the following because of ConcurrentModificationException :
26 Answers
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What is the HTML tabindex attribute?
...ard events (e.g. 'onkeypress') is to make such elements focusable. Lastly, if you don't want to set the order but just make your element focusable use tabindex="0" on all such elements:
<div tabindex="0"></div>
Also, if you don't want it to be focusable via the tab key then use tabind...
git replacing LF with CRLF
...hen does this warning show up (under Windows)
– autocrlf = true if you have unix-style lf in one of your files (= RARELY),
– autocrlf = input if you have win-style crlf in one of your files (= almost ALWAYS),
– autocrlf = false – NEVER!
What does this warning mean
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How do I make and use a Queue in Objective-C?
...t-in-first-out, so we remove objects from the head
- (id) dequeue {
// if ([self count] == 0) return nil; // to avoid raising exception (Quinn)
id headObject = [self objectAtIndex:0];
if (headObject != nil) {
[[headObject retain] autorelease]; // so it isn't dealloc'ed on remove
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Detecting an “invalid date” Date instance in JavaScript
I'd like to tell the difference between valid and invalid date objects in JS, but couldn't figure out how:
46 Answers
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Cannot set boolean values in LocalStorage?
...mentation of Storage can only store strings, but on 2009 September, W3C modified the draft to accept any data. The implementation (still) isn't caught up yet (see Edit below).
So in your case the boolean is converted to a string.
As for why "true" != true, as written in the description of Equal (=...