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Can a foreign key be NULL and/or duplicate?
...t in a different table (the parent table). That is all an FK is by definition. Null by definition is not a value. Null means that we do not yet know what the value is.
Let me give you a real life example. Suppose you have a database that stores sales proposals. Suppose further that each proposal on...
Configure Sublime Text on OS X to show full directory path in title bar
On Linux, Sublime Text shows the full path of my currently open file in the title bar by default, but on OS X, it only shows the name of the file.
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Android: How can I get the current foreground activity (from a service)?
...may not own the "currently running Activity".
I have a service running on the background, and I would like to update my current Activity when an event occurs (in the service). Is there a easy way to do that (like the one I suggested above)?
Send a broadcast Intent to the activity -- here is a...
When should I use OWIN Katana?
I am new to OWIN and Katana. I really don't get why I should use OWIN, while I can use IIS . To simplify, my question is: What do I lose if I skip learning OWIN and use IIS for my websites?
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Are there any HTTP/HTTPS interception tools like Fiddler for mac OS X? [closed]
I would like to know if there are any applications like fiddler but for mac OS X, as I need to debug some requests from web applications in Mac OS X. I used to do it with fiddler on Windows and would love to have this tool available on Mac as well.
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Clean up a fork and restart it from the upstream
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The simplest solution would be (using 'upstream' as the remote name referencing the original repo forked):
git remote add upstream /url/to/original/repo
git fetch upstream
git checkout master
git reset --hard upstream/master
git push origin ...
multi-step registration process issues in asp.net mvc (split viewmodels, single model)
I have a multi-step registration process , backed by a single object in domain layer , which have validation rules defined on properties.
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Fatal error: Class 'ZipArchive' not found in
I have a problem that I install 'Archive_Zip 0.1.1' on Linux server, but when I try to run the script to create the zip file it gives the fatal error
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How can I install pip on Windows?
...cement for easy_install . But should I install pip using easy_install on Windows? Is there a better way?
38 Answers
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Difference between natural join and inner join
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One significant difference between INNER JOIN and NATURAL JOIN is the number of columns returned.
Consider:
TableA TableB
+------------+----------+ +--------------------+
|Column1 | ...