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How to select unique records by SQL
...umns (at least on a DB2), which still will return duplicate values in individual columns.
– Konstantin
Jan 4 '18 at 10:46
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What is the difference between “INNER JOIN” and “OUTER JOIN”?
...ally show any distinction between different types of join predicate or provide a framework for reasoning about how they will operate.
There is no substitute for understanding the logical processing and it is relatively straightforward to grasp anyway.
Imagine a cross join.
Evaluate the on clause ag...
How do I verify/check/test/validate my SSH passphrase?
...er passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /tmp/my_key.
Your public key has been saved in /tmp/my_key.pub.
The key fingerprint is:
de:24:1b:64:06:43:ca:76:ba:81:e5:f2:59:3b:81:fe rob@Robs-MacBook-Pro.local
The key's randomart image is:...
How do I avoid the specification of the username and password at every git push?
..., go to settings and click 'add SSH key'. Copy the contents of your ~/.ssh/id_rsa.pub into the field labeled 'Key'.
If your repository is administered by somebody else, give the administrator your id_rsa.pub.
If your remote repository is administered by your, you can use this command for example:
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Web API 最佳入门指南 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...e of clients, including browsers and mobile devices. ASP.NET Web API is an ideal platform for building RESTful applications on the .NET Framework.
Web API在ASP.NET完整框架中地位如下图，与SignalR一起同为构建Service而服务的框架。Web API负责构建http常规服务，而Sin...
How to get MVC action to return 404
...ttpNotFound();
}
or
if (notWhatIExpected)
{
return HttpNotFound("I did not find message goes here");
}
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What happens if you call erase() on a map element while iterating from begin to end?
...;
while(pm_it != port_map.end())
{
if (pm_it->second == delete_this_id)
{
pm_it = port_map.erase(pm_it);
}
else
{
++pm_it;
}
}
C++03
Erasing elements in a map does not invalidate any iterators.
(apart from iterators on the element that was deleted)
Actu...
Show hide fragment in android
I am developing application which contains 2 fragments and i want to show hide according to my need. Following code has simple example of my problem.
This simple Fragmentactivity contains 1 button and one listfragment.
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delete_all vs destroy_all?
...ach to delete records from a table. For instance, I have a user whose user ID is across many tables. I want to delete this user and every record that has his ID in all tables.
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python pandas dataframe to dictionary
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See the docs for to_dict. You can use it like this:
df.set_index('id').to_dict()
And if you have only one column, to avoid the column name is also a level in the dict (actually, in this case you use the Series.to_dict()):
df.set_index('id')['value'].to_dict()
...