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Add unique constraint to combination of two columns
...g an exception (exceptions are expensive).
http://www.sqlperformance.com/2012/08/t-sql-queries/error-handling
http://www.mssqltips.com/sqlservertip/2632/checking-for-potential-constraint-violations-before-entering-sql-server-try-and-catch-logic/
If you want to prevent exceptions from bubbling up ...
Ruby: Merging variables in to a string
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answered Feb 16 '09 at 21:42
Mike WoodhouseMike Woodhouse
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How to do version numbers? [closed]
...e "unstable watchout" on there. So how would you go about versioning? Is 1.0 stable? Should the build date be in the version number? Tell me what you guys think!
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Is there any way to prevent input type=“number” getting negative values?
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Use the min attribute like this:
<input type="number" min="0">
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how to find host name from IP with out login to the host
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Use nslookup
nslookup 208.77.188.166
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Non-authoritative answer:
166.188.77.208.in-addr.arpa name = www.example.com.
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Sass negative variable value?
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Try it like this
margin: 0 (-$pad) 20px (-$pad);
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Cluster analysis in R: determine the optimal number of clusters
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1024
If your question is how can I determine how many clusters are appropriate for a kmeans analysi...
Can I use `pip` instead of `easy_install` for `python setup.py install` dependency resolution?
...ip install https://pypi.python.org/packages/source/r/requests/requests-2.3.0.tar.gz
Install from local tarball
wget https://pypi.python.org/packages/source/r/requests/requests-2.3.0.tar.gz
pip install requests-2.3.0.tar.gz
Install from local folder
tar -zxvf requests-2.3.0.tar.gz
cd requests-2...
Overlaying histograms with ggplot2 in R
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Your current code:
ggplot(histogram, aes(f0, fill = utt)) + geom_histogram(alpha = 0.2)
is telling ggplot to construct one histogram using all the values in f0 and then color the bars of this single histogram according to the variable utt.
What you want instead is...
Emulating a do-while loop in Bash
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answered May 10 '13 at 19:59
jm666jm666
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