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how to emulate “insert ignore” and “on duplicate key update” (sql merge) with postgresql?
...gsql-control-structures.html, example 40-2 right at the bottom.
That's usually the easiest way. You can do some magic with rules, but it's likely going to be a lot messier. I'd recommend the wrap-in-function approach over that any day.
This works for single row, or few row, values. If you're deali...
MySQL and GROUP_CONCAT() maximum length
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Rackspace and other cloud servers don't allow GLOBAL access. I try using jdbc.execute("SET SESSION group_concat_max_len = ..."); inside the Dao initialize method but as keatkeat has stated, this is only temporary. If anyone knows the right way to make this change p...
Is there any overhead to declaring a variable within a loop? (C++)
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Stack space for local variables is usually allocated in function scope. So no stack pointer adjustment happens inside the loop, just assigning 4 to var. Therefore these two snippets have the same overhead.
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Signed to unsigned conversion in C - is it always safe?
...herwise, if the type of the operand with signed integer type can represent all of the values of the type of the operand with unsigned integer type, then the operand with unsigned integer type is converted to the type of the operand with signed integer type.
Otherwise, both operands are converted t...
Find unique rows in numpy.array
...e((np.void, a.dtype.itemsize * a.shape[1]))) ?
– Akavall
Jun 7 '13 at 0:28
3
@Akavall It is creat...
Read values into a shell variable from a pipe
...e, what worked for me was (a different example but similar usage): pip install -U echo $(ls -t *.py | head -1). In case, someone ever has a similar problem and stumbles upon this answer like me.
– ivan_bilan
Mar 14 '19 at 15:25
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Random number generation in C++11: how to generate, how does it work? [closed]
...ad about it (what is that engine , maths term like distribution , "where all integers produced are equally likely ").
2...
Set android shape color programmatically
...er has been updated to cover the scenario where background is an instance of ColorDrawable. Thanks Tyler Pfaff, for pointing this out.
The drawable is an oval and is the background of an ImageView
Get the Drawable from imageView using getBackground():
Drawable background = imageView.getBackgr...
Why are regular expressions so controversial? [closed]
...ions. And not just slow, but the performance of the regex engine can be totally unpredictable when faced with arbitrary (user-supplied) inputs.
– Pacerier
Dec 1 '15 at 21:53
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Is Unit Testing worth the effort? [closed]
...en and personal benefits as well as the obvious ones that you just can't really explain to somebody until they're doing it themselves.
But, ignoring that, here's my attempt!
Unit Tests allows you to make big changes to code quickly. You know it works now because you've run the tests, when you ma...