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mongoDB/mongoose: unique if not null
I was wondering if there is way to force a unique collection entry but only if entry is not null .
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Sample schema:
4 Answ...
What is a Manifest in Scala and when do you need it?
Since Scala 2.7.2 there is something called Manifest which is a workaround for Java's type erasure. But how does Manifest work exactly and why / when do you need to use it?
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Build the full path filename in Python
I need to pass a file path name to a module. How do I build the file path from a directory name, base filename, and a file format string?
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Explain which gitignore rule is ignoring my file
... there any way to see why some file is getting ignored by git (i.e. which rule in a .gitignore file is causing the file to be ignored)?
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Which concurrent Queue implementation should I use in Java?
...cteristics and blocking behavior.
Taking the easiest first, ArrayBlockingQueue is a queue of a fixed size. So if you set the size at 10, and attempt to insert an 11th element, the insert statement will block until another thread removes an element. The fairness issue is what happens if multiple thr...
What is the difference between Pan and Swipe in iOS?
Sounds simple .. Hold the Trackpad, move the finger, release .. But somehow swipe is not being triggered (pan is triggered instead)
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ASP.NET MVC A potentially dangerous Request.Form value was detected from the client when using a cus
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You have a few options.
On the model add this attribute to each property that you need to allow HTML - best choice
using System.Web.Mvc;
[AllowHtml]
public string SomeProperty { get; set; }
On the controller action add thi...
Adding up BigDecimals using Streams
...ave a collection of BigDecimals (in this example, a LinkedList ) that I would like to add together. Is it possible to use streams for this?
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Execute and get the output of a shell command in node.js
In a node.js, I'd like to find a way to obtain the output of a Unix terminal command. Is there any way to do this?
5 Answer...
How many GCC optimization levels are there?
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To be pedantic, there are 8 different valid -O options you can give to gcc, though there are some that mean the same thing.
The original version of this answer stated there were 7 options. GCC has since added -Og to bring the total to 8
From the man page:
-O (Same as -O1) ...