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How do I specify unique constraint for multiple columns in MySQL?
...mple:
PRODUCT_NAME, PRODUCT_VERSION
'glass', null
'glass', null
'wine', 1
Now if you try to insert ('wine' 1) again it will report a constraint violation
Hope this helps
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What does .SD stand for in data.table in R
.SD looks useful but I do not really know what I am doing with it. What does it stand for? Why is there a preceding period (full stop). What is happening when I use it?
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Mock framework vs MS Fakes frameworks
... like this:
using (ShimsContext.Create())
{
System.Fakes.ShimDateTime.NowGet = () => { return new DateTime(fixedYear, 1, 1); };
}
My worry with shims is that people will start seeing them as "an easier way to unit test" because it doesn't force you to write code the way you should. For a ...
Location Manager Error : (KCLErrorDomain error 0)
...ch ????????????????????????????????????????. Editing my question for more knowledge :)
– Vaibhav Saran
Sep 15 '14 at 11:14
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Load different colorscheme when using vimdiff
...e past, but just added it to my .vimrc in the 'if &diff' predicate and now saved some keystrokes
– qneill
Jan 24 '19 at 17:07
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How to extract year and month from date in PostgreSQL without using to_char() function?
... That's right. U can use to compare: date(date_trunc( 'month', now())) = to_Date(5::varchar || ' ' || 2017::varchar, 'mm YYYY')
– Alejandro Salamanca Mazuelo
May 19 '17 at 21:22
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How can I get the full/absolute URL (with domain) in Django?
...could add the s, but do you develop with https locally? and do you always know, if you have https but not sometimes...?
– tjati
May 5 '14 at 12:30
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git visual diff between branches
...with gitk.
> gitk branch1 branch2
First click on the tip of branch1. Now right-click on the tip of branch2 and select Diff this->selected.
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How can I declare and define multiple variables in one line using C++?
...InputValue, presentInputValue;) or if they just happen to be the same type now but don't really need to be (uint8_t height, width; might turn into uint8_t height; uint16_t width; in the future and should have been uint8_t height; uint8_t width; to begin with).
– altendky
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Detect Safari browser
...re are many legitimate use cases for browser detection. Do not presume to know the asker or answerer's intention. While it's great to include a helpful tip you may believe to be relevant, it's by no means a requirement.
– Ruben Martinez Jr.
Apr 10 '18 at 13:56
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