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mongoDB/mongoose: unique if not null
... or object when not null).
If you're not interested in the details, feel free to skip to the implementation section.
longer version
To supplement @Nolan's answer, starting with MongoDB v3.2 you can use a partial unique index with a filter expression.
The partial filter expression has limitation...
Where to find Application Loader app in Mac?
...oject, I'll update this post when i have an answer.
In the mean time more info can be found here.
Developer Apple - Whats new
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How to validate phone numbers using regex
...r based on the number itself; able to distinguish Fixed-line, Mobile, Toll-free, Premium Rate, Shared Cost, VoIP and Personal Numbers (whenever feasible).
isNumberMatch - gets a confidence level on whether two numbers could be the same.
getExampleNumber/getExampleNumberByType - provides valid exampl...
Which concurrent Queue implementation should I use in Java?
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ConcurrentLinkedQueue is lock-free, LinkedBlockingQueue is not. Every time you invoke LinkedBlockingQueue.put() or LinkedBlockingQueue.take(), you need acquire the lock first. In other word, LinkedBlockingQueue has poor concurrency. If you care performanc...
How to compile a 64-bit application using Visual C++ 2010 Express?
...es for the x64 platform. I had to install the compilers update here. More info at KB2519277.
– kipkennedy
Dec 30 '11 at 23:48
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How to check if APK is signed or “debug build”?
...ase certificate, but the following way seems best to me.
According to the info in Android documentation Signing Your Application, debug key contain following subject distinguished name: "CN=Android Debug,O=Android,C=US". We can use this information to test if package is signed with debug key wit...
How slow are .NET exceptions?
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unfortunately, people are told exceptions are free, use them for trivial 'correct' functionality, they should be used as you say, when things have gone wrong - in 'exceptional' circumstances
– gbjbaanb
Oct 2 '08 at 12:36
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How to pass password to scp?
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>> brew info sshpass Error: No available formula with the name "sshpass" We won't add sshpass because it makes it too easy for novice SSH users to ruin SSH's security. ;)
– Lukas N.P. Egger
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Putting an if-elif-else statement on one line?
...just as a curiosity:
x = (i>100 and 2) or (i<100 and 1) or 0
More info here: https://docs.python.org/3/library/stdtypes.html#boolean-operations-and-or-not
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How to query MongoDB with “like”?
...regular expressions you can create any pattern that you imagine.
For more info on regular expressions refer to this link
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions
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