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How to open a file for both reading and writing?
...ovided number of bytes, i.e. removes all of the file content after the specified number of bytes. Imagine that your file has the string Hello, world and you write Bye. If you don't truncate() the content at the end will be Byelo, world, since you never deleted the text that existed in the file. trun...
Spring MVC - How to get all request params in a map in Spring controller?
...ct directly. The answer is actually quite simple and what you would expect if you're familiar with Spring MVC.
@RequestMapping(value = {"/search/", "/search"}, method = RequestMethod.GET)
public String search(
@RequestParam Map<String,String> allRequestParams, ModelMap model) {
return "vie...
COUNT(*) vs. COUNT(1) vs. COUNT(pk): which is better? [duplicate]
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Use either COUNT(field) or COUNT(*), and stick with it consistently, and if your database allows COUNT(tableHere) or COUNT(tableHere.*), use that.
In short, don't use COUNT(1) for anything. It's a one-trick pony, which rarely does what you want, and in those rare cases is equivalent to count(*)...
What is a “cache-friendly” code?
What is the difference between " cache unfriendly code " and the " cache friendly " code?
9 Answers
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Why Collections.sort uses merge sort instead of quicksort?
...ly from Josh Bloch §:
I did write these methods, so I suppose I'm qualified to answer. It is
true that there is no single best sorting algorithm. QuickSort has
two major deficiencies when compared to mergesort:
It's not stable (as parsifal noted).
It doesn't guarantee n log n per...
MongoDB/NoSQL: Keeping Document Change History
...equirement in database applications is to track changes to one or more specific entities in a database. I've heard this called row versioning, a log table or a history table (I'm sure there are other names for it). There are a number of ways to approach it in an RDBMS--you can write all changes fr...
Is there a performance difference between CTE , Sub-Query, Temporary Table or Table Variable?
In this excellent SO question , differences between CTE and sub-queries were discussed.
4 Answers
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Node.js + Express: Routes vs controller
... pattern, and a route handler can certainly serve the role of a controller if you so desire--but you have to set it up that way. A great example can be found in the Express examples folder, called mvc. If you look at lib/boot.js, you can see how they've set up the example to require each file in the...
Listen for key press in .NET console app
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but if you do this instead of readLine() you lose the awesome feature of having history recall by pressing "up" key.
– v.oddou
Jul 1 '15 at 8:17
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Is there a difference between x++ and ++x in java?
Is there a difference between ++x and x++ in java?
16 Answers
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