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SQL - find records from one table which don't exist in another
...presents the intent. If performance not good enough, make sure appropriate indexes exist. Only then, try the less-obvious LEFT OUTER JOIN, see if its performance is better.
– ToolmakerSteve
Feb 24 '19 at 2:05
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In pure functional languages, is there an algorithm to get the inverse function?
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In some cases, yes! There's a beautiful paper called Bidirectionalization for Free! which discusses a few cases -- when your function is sufficiently polymorphic -- where it is possible, completely automatically to derive an inverse function. (It also discusses what makes...
How to install PyQt4 on Windows using pip?
...ld than just a pure python code package, which means it can be hard to install it from source.
Make sure you grab the correct Windows wheel file (python version, 32/64 bit), and then use pip to install it - e.g:
C:\path\where\wheel\is\> pip install PyQt4-4.11.4-cp35-none-win_amd64.whl
Should ...
Can't get Gulp to run: cannot find module 'gulp-util'
On Windows 7, I've installed gulp as explained here: http://markgoodyear.com/2014/01/getting-started-with-gulp/ :
10 Answe...
What does it mean to “program to an interface”?
...r more likely, use the Queue interface). If I know I need random access by index, I'd pick the ArrayList concrete class.
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Finding out the name of the original repository you cloned from in Git
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In the repository root, the .git/config file holds all information about remote repositories and branches. In your example, you should look for something like:
[remote "origin"]
fetch = +refs/heads/*:refs/remotes/origin/*
url = server:gitRepo.git
Also, the Git comm...
Where can I find the IIS logs?
... in my local IIS. I've created a website exactly as explained in their install guide, but am having some problems, and would like to see what the IIS log has to say. Embarrassingly enough, the problem is I can't find the log files!
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Insert/Update Many to Many Entity Framework . How do I do it?
...te.IsValid)
{
db.SaveChanges();
return RedirectToAction("Index");
}
return View(mathClassModel);
}
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Rails new vs create
...a GET to serve the form version of that or in other words, the new action. Index and show are also GETs, update is a PUT (or PATCH in Rails 4+), and destroy is a DELETE in HTTP.
In addition, it nicely separates the logic in the controller and gives you a smooth way to deal with errors (by re-render...
What is 'Pattern Matching' in functional languages?
...wesome.
Algebraic data types in a nutshell
ML-like functional languages allow you define simple data types called "disjoint unions" or "algebraic data types". These data structures are simple containers, and can be recursively defined. For example:
type 'a list =
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| Cons of 'a * 'a ...