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Why are joins bad when considering scalability?
...en so can you.
There are many reasons not to denomalize. First, speed of select queries is not the only or even main concern with databases. Integrity of the data is the first concern. If you denormalize then you have to put into place techniques to keep the data denormalized as the parent data ch...
How to upload a file in Django? [closed]
...ss DocumentForm(forms.Form):
docfile = forms.FileField(
label='Select a file',
help_text='max. 42 megabytes'
)
4. View: myproject/myapp/views.py
A view where all the magic happens. Pay attention how request.FILES are handled. For me, it was really hard to spot the fact tha...
Setting environment variables via launchd.conf no longer works in OS X Yosemite/El Capitan/macOS Sie
... If the computer is restarted and "Reopen windows when logging back in" is selected, the reopened windows may not see the variables (Perhaps they are opened before the agent is run). Also, if you log in via ssh, the variables will not be set (so you'll need to set them in ~/.bash_profile). Finally, ...
Spring @Transactional - isolation, propagation
...ion. I think if you understand the dirty reads concept you will be able to select a good option.
Example of when a dirty read can occur:
thread 1 thread 2
| |
write(x) |
| |
| read(x)
| |
rollback |
v v...
How do you specify the Java compiler version in a pom.xml file?
... Which way is "best"? This one is less verbose compared to the selected answer, but it seems sort of hidden. Even the Maven site documentation shows using the plugin.
– mkobit
Oct 15 '15 at 16:34
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In which case do you use the JPA @JoinTable annotation?
... UPDATE There aren't duplicates entries in my database, the hibernate is selecting with the left outer join and I dont know why..
– MaikoID
Dec 12 '12 at 20:49
2
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How do I replace NA values with zeros in an R dataframe?
... mutate(myCol1 = if_else(is.na(myCol1), 0, myCol1))
Note: This works per selected column, if we need to do this for all column, see @reidjax's answer using mutate_each.
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What are the main uses of yield(), and how does it differ from join() and interrupt()?
... calling yield(), there's still no guarantee that the same thread won't be selected for execution again, given a pool of equal priority threads.
– Andrew Fielden
Aug 8 '11 at 9:20
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Why not inherit from List?
...is the collective name given to a group of players ... Such teams could be selected to play in a match against an opposing team, to represent a football club ...". So it is my opinion that a team is a list of players (or perhaps more accurately a collection of players).
– Ben
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Is there ever a time where using a database 1:1 relationship makes sense?
...re is a larger set of data that needs to be collected, if and only if they select to have health coverage. I would keep the demographic data regarding health coverage in a different table to both give easier security partitioning and to avoid hauling that data around in queries unrelated to insuranc...