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When saving, how can you check if a field has changed?
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Really perfect, and do not perform extra query. Thanks a lot !
– Stéphane
Mar 4 '13 at 10:26
29
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How important is the order of columns in indexes?
...mns involved.
Giving that rationale, the only difference is comparing two 'strings' that differ earlier versus later in the string. This is a tiny part of the total cost. There is no "first pass / second pass", as mentioned in one Answer.
So, what order should be used?
Start with column(s) tested...
Odd behavior when Java converts int to byte?
...e number as negative
public class castingsample{
public static void main(String args[]){
int i;
byte y;
i = 1024;
for(i = 1024; i > 0; i-- ){
y = (byte)i;
System.out.print(i + " mod 128 = " + i%128 + " also ");
System.out.println(i + " cast to byte " + " = " ...
Or versus OrElse
... the right operand won't even be evaluated (this is useful in cases like:
string a;
//...
if (a is null) or (a = "Hi") //...
to avoid a NullReferenceException throw by the right-hand operand.
I'm sincerely astonished that this (lazy evaluation) isn't the default behaviour of or and and as it is ...
Does reading an entire file leave the file handle open?
...
Instead of retrieving the file content as a single string,
it can be handy to store the content as a list of all lines the file comprises:
with open('Path/to/file', 'r') as content_file:
content_list = content_file.read().strip().split("\n")
As can be seen, one needs t...
Difference between Char.IsDigit() and Char.IsNumber() in C#
...(c)))
{
File.AppendAllText("IsNumberLike.txt", string.Format("{0},{1},{2},&#{3};,{4},{5}\n", i, c, Char.GetUnicodeCategory(c), i, Char.IsNumber(c), Char.IsDigit(c)));
}
}
}
Result looks following: As you can see there is stuff that one would ...
What does the `forall` keyword in Haskell/GHC do?
... b)
ghci> liftTup (\x -> [x]) (5, "Hello")
No instance for (Num [Char])
...
ghci> -- huh?
ghci> :t liftTup
liftTup :: (t -> t1) -> (t, t) -> (t1, t1)
"Hmm.. why does GHC infer that the tuple must contain two of the same type? Let's tell it they don't have to be"
-- te...
Converting String to Int with Swift
...to calculate acceleration. However, since the values in the text boxes are string, I am unable to convert them to integers.
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Make a link use POST instead of GET
... tab to the url of the href
As the method is POST, we should have no query string in the URL of the target page we load
That page should receive the data in parameters (names and value) by POST
I am using jquery here, but this could be done with native apis (harder and longer of course).
<html...
Why do people say there is modulo bias when using a random number generator?
... particularly hard to avoid in computing, where numbers are represented as strings of bits: 0s and 1s. Finding truly random sources of randomness is also extremely difficult, but is beyond the scope of this discussion. For the remainder of this answer, assume that there exists an unlimited source of...