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Transaction isolation levels relation with locks on table
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I want to understand the lock each transaction isolation takes on the table
For example, you have 3 concurrent processes A, B and C. A starts a transaction, writes data and commit/rollback (depending on results). B just executes a SELECT st...
Explicitly calling return in a function or not
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Question was: Why is not (explicitly) calling return faster or better, and thus preferable?
There is no statement in R documentation making such an assumption.
The main page ?'function' says:
function( arglist ) expr
return(value)
Is it faster without calling return?
Both function() and re...
Keep file in a Git repo, but don't track changes
...t solution to do this. First change the file you do not want to be tracked and use the following command:
git update-index --assume-unchanged FILE_NAME
and if you want to track the changes again use this command:
git update-index --no-assume-unchanged FILE_NAME
git-update-index documentation...
Difference between & and && in Java? [duplicate]
I was just wondering what the difference between & and && is?
A few days I wrote a condition for an if statement the looked something like:
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What does static_assert do, and what would you use it for?
...n example where static_assert(...) ('C++11') would solve the problem in hand elegantly?
8 Answers
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Positioning element at center of screen
...creen irrespective of screen size. In other words, the space left on 'top' and 'bottom' should be equal and space left on 'right' and 'left' sides should be equal. I would like to accomplish this with only CSS.
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What is middleware exactly?
...on of middleware? When I look into middleware, I find a lot of information and some definitions, but while reading these information and definitions, it seems that mostly all 'wares' are in the middle of something. So, are all things middleware?
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Map enum in JPA with fixed values?
...m using JPA. I especially want to set the integer value of each enum entry and to save only the integer value.
9 Answers
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virtualenv --no-site-packages and pip still finding global packages?
...on that virtualenv --no-site-packages would create a completely separate and isolated Python environment, but it doesn't seem to.
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“No X11 DISPLAY variable” - what does it mean?
...erent userid, this will fail.
If you're coming in from another machine, and you're at the main display of that machine and it's running X, then you can use "ssh -X hostname" to connect to that host, and ssh will forward the X display back. ssh will also make sure that the DISPLAY environment var...