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MySQL Error 1215: Cannot add foreign key constraint
... I think they need to be of the same charset and collation. (Or possibly 1-byte and 2-byte charsets are not compatible.)
– Graham Charles
Jan 21 '14 at 1:31
6
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Why is SSE scalar sqrt(x) slower than rsqrt(x) * x?
...ind an instruction sequence (reciprocal square-root approximation followed by a single Newton-Raphson step) that gives nearly full precision (~23 bits of accuracy, if I remember properly), and is still somewhat faster than sqrtss.
edit: If speed is critical, and you're really calling this in a loop...
SignalR: Why choose Hub vs. Persistent Connection?
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There are two ways to use SignalR: you can access it at a low level by overriding its PersistentConnection class, which gives you a lot of control over it; or you can let SignalR do all of the heavy lifting for you, by using the high level ‘Hubs’.
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What's “P=NP?”, and why is it such a famous question? [closed]
... a different state. This is called a state transition. Amazingly enough, by carefully constructing states and transitions, you can design a TM, which is equivalent to any computer program that can be written. This is why it is used as a theoretical model for proving things about what computers ca...
Python's json module, converts int dictionary keys to strings
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Answering your subquestion:
It can be accomplished by using json.loads(jsonDict, object_hook=jsonKeys2int)
def jsonKeys2int(x):
if isinstance(x, dict):
return {int(k):v for k,v in x.items()}
return x
This function will also work for nested dicts and use...
Android Closing Activity Programmatically
... says finish() - so there isn't much to be gained for you or the community by repeating it. Sorry to be the bearer of bad news. In any case welcome to Stackoverflow, thanks for trying - hope you have better luck next time!
– kenny_k
Sep 17 '19 at 12:15
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No Multiline Lambda in Python: Why not?
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This is a simple ambiguity that must be solved by adding an extra set of parens, something that exists in many places already, e.g. generator expressions surrounded by other arguments, calling a method on an integer literal (although this need not be the case since a func...
Updating MySQL primary key
..., user_1, type, max(timestamp), count(*) n from user_interactions u
group by user_2, user_1, type
having n > 1;
delete u from user_interactions u, fixit
where fixit.user_2 = u.user_2
and fixit.user_1 = u.user_1
and fixit.type = u.type
and fixit.timestamp != u.timestamp;
alter table u...
How can I wrap or break long text/word in a fixed width span?
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By default a span is an inline element... so that's not the default behavior.
You can make the span behave that way by adding display: block; to your CSS.
span {
display: block;
width: 100px;
}
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How to add a separator to a WinForms ContextMenu?
...mber the syntax. I ended up pulling up some old VC++ 6 files to find it. By the way, I still occasionally refer to "The Petzold Book" for some things. Wow, I'm feeling old...
– Brad Bruce
Aug 29 '09 at 1:27
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