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Create unique constraint with null columns
...(user_id, menu_id, recipe_id), you cannot base CLUSTER on a partial index, and queries without a matching WHERE condition cannot use the partial index. (It seems unlikely you'd want a FK reference three columns wide - use the PK column instead).
If you need a complete index, you can alternatively d...
Permission denied (publickey) when deploying heroku code. fatal: The remote end hung up unexpectedly
I'm attempting to deploy my code to heroku with the following command line:
34 Answers
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Firebug says “No Javascript on this page”, even though JavaScript does exist on the page
...functionality but Firebug per se is never going to be fixed for Firefox 50 and beyond
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Xcode: issue “file xxx.png is missing from working copy” at project building
...answered Aug 19 '16 at 8:47
Alexander VaseninAlexander Vasenin
10.8k33 gold badges3737 silver badges6262 bronze badges
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What's faster, SELECT DISTINCT or GROUP BY in MySQL?
...if you DON'T have an index (as it doesn't sort). When you do have an index and it's used, they're synonyms.
– Quassnoi
Feb 27 '09 at 15:11
10
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What is the difference between the add and offer methods in a Queue in Java?
... element can not be added to collection the add method throws an exception and offer doesn't.
From: http://java.sun.com/j2se/1.5.0/docs/api/java/util/Collection.html#add%28E%29
If a collection refuses to add a
particular element for any reason
other than that it already contains
the eleme...
How to use NSJSONSerialization
..."id": "2", "name":"Bbb"}]
This might give you a clear picture of how to handle it:
NSError *e = nil;
NSArray *jsonArray = [NSJSONSerialization JSONObjectWithData: data options: NSJSONReadingMutableContainers error: &e];
if (!jsonArray) {
NSLog(@"Error parsing JSON: %@", e);
} else {
for...
Why java.lang.Object is not abstract? [duplicate]
...e argued that some of the methods would benefit from this. Take hashCode() and equals() for instance, there would probably have been a lot less frustration around the complexities of these two if they had both been made abstract. This would require developers to figure out how they should be impleme...
Have a div cling to top of screen if scrolled down past it [duplicate]
...has scrolled past it.
This is done with something like this, attaching a handler to the window.scroll event
// Cache selectors outside callback for performance.
var $window = $(window),
$stickyEl = $('#the-sticky-div'),
elTop = $stickyEl.offset().top;
$window.scroll(functi...
Do I encode ampersands in ?
I'm writing code that automatically generates HTML, and I want it to encode things properly.
4 Answers
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