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What is the “N+1 selects problem” in ORM (Object-Relational Mapping)?
...erally stated as a problem in Object-Relational mapping (ORM) discussions, and I understand that it has something to do with having to make a lot of database queries for something that seems simple in the object world.
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Center a map in d3 given a geoJSON object
... you have a geoJSON object that you are going to draw you have to scale it and translate it in order to get it to the size that one wants and translate it in order to center it. This is a very tedious task of trial and error, and I was wondering if anyone knew a better way to obtain these values?
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Big O, how do you calculate/approximate it?
Most people with a degree in CS will certainly know what Big O stands for .
It helps us to measure how well an algorithm scales.
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Using async/await for multiple tasks
....Select(i => DoSomething(1, i, blogClient)).ToArray());
On the other hand, the above code with WaitAll also blocks the threads and your threads won't be free to process any other work till the operation ends.
Recommended Approach
I would prefer WhenAll which will perform your operations asyn...
How do I get both STDOUT and STDERR to go to the terminal and a log file?
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Use "tee" to redirect to a file and the screen. Depending on the shell you use, you first have to redirect stderr to stdout using
./a.out 2>&1 | tee output
or
./a.out |& tee output
In csh, there is a built-in command called "script" that...
What's the difference between echo, print, and print_r in PHP?
I use echo and print_r much, and almost never use print .
11 Answers
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Generating random whole numbers in JavaScript in a specific range?
How can I generate random whole numbers between two specified variables in JavaScript, e.g. x = 4 and y = 8 would output any of 4, 5, 6, 7, 8 ?
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What is the best way to compute trending topics or tags?
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This problem calls for a z-score or standard score, which will take into account the historical average, as other people have mention, but also the standard deviation of this historical data, making it more robust than just using the average.
In your case a z-sc...
Is there ever a time where using a database 1:1 relationship makes sense?
I was thinking the other day on normalization, and it occurred to me, I cannot think of a time where there should be a 1:1 relationship in a database.
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How to use php serialize() and unserialize()
... means to put the structure into a "lower common denominator" that can be handled by things other than PHP, like databases, text files, sockets. The standard PHP function serialize is just a format to express such a thing, it serializes a data structure into a string representation that's unique to ...