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SQL UPDATE SET one column to be equal to a value in a related table referenced by a different column
...QuestionAnswers a
on q.AnswerID = a.AnswerID
where q.QuestionID is null -- and other conditions you might want
I recommend to check what the result set to update is before running the update (same query, just with a select):
select *
from QuestionTrackings q
inner join QuestionAnswers a
on q.Answ...
Ideal Ruby project structure
... directory you want onto that using the $: variable. i.e.
$:.push File.expand_path(File.dirname(__FILE__) + '/../surfcompstuff')
That means when you have say, surfer.rb in that dir, you can require "surfer" anywhere and the file will be found.
Also, as a convention, classes and singletons get a ...
How to change the author and committer name and e-mail of multiple commits in Git?
I was writing a simple script in the school computer, and committing the changes to Git (in a repo that was in my pendrive, cloned from my computer at home). After several commits I realized I was committing stuff as the root user.
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how do you push only some of your local git commits?
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Assuming your commits are on the master branch and you want to push them to the remote master branch:
$ git push origin master~3:master
If you were using git-svn:
$ git svn dcommit master~3
In the case of git-svn, you could also use HEAD~3, since it is expecting a c...
Why can't strings be mutable in Java and .NET?
Why is it that they decided to make String immutable in Java and .NET (and some other languages)? Why didn't they make it mutable?
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Build Eclipse Java Project from Command Line
Is there a way to compile an Eclipse-based Java project from the command line?
8 Answers
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Convert float to double without losing precision
I have a primitive float and I need as a primitive double. Simply casting the float to double gives me weird extra precision. For example:
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How to properly create an SVN tag from trunk?
...ation to use; it lets Subversion keep track of the history of these files, and also (I assume) store them much more efficiently.
In my experience, it's best to do copies ("snapshots") of entire projects, i.e. all files from the root check-out location. That way the snapshot can stand on its own, as...
How do I calculate the normal vector of a line segment?
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if we define dx=x2-x1 and dy=y2-y1, then the normals are (-dy, dx) and (dy, -dx).
Note that no division is required, and so you're not risking dividing by zero.
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Is there a pattern for initializing objects created via a DI container
I am trying to get Unity to manage the creation of my objects and I want to have some initialization parameters that are not known until run-time:
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