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How to avoid mysql 'Deadlock found when trying to get lock; try restarting transaction'
...each connection will wait for the other to release the key -> deadlock.
Now, if you changed your queries such that the connections would lock the keys at the same order, ie:
connection 1: locks key(1), locks key(2);
connection 2: locks key(1), locks key(2);
it will be impossible to get a deadlo...
Does Foreign Key improve query performance?
...pretty much useless because it doesn't answer the question. It's great to know that foreign keys are not intended to have a (positive) effect on performance, but the question was concerning reality, not intentions.
– John
Mar 15 '17 at 16:04
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How to use android emulator for testing bluetooth application?
... adapter to 'Bridged'. ·
Start the VM and select 'Live CD VESA' at boot.
Now you need to find out the IP of this VM. Go to terminal in VM (use Alt+F1
& Alt+F7 to toggle) and use the netcfg command to find this.
Now you need open a command prompt and go to your android install
folder (on host)...
Python assigning multiple variables to same value? list behavior
...t element of a to 1, the first elements of b and c are 1.
If you want to know if two names are naming the same object, use the is operator:
>>> a=b=c=[0,3,5]
>>> a is b
True
You then ask:
what is different from this?
d=e=f=3
e=4
print('f:',f)
print('e:',e)
Here, you'r...
Clean up a fork and restart it from the upstream
...otect it after force-pushing).
Note: on GitHub specifically, there is now (February 2019) a shortcut to delete forked repos for pull requests that have been merged upstream.
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Java string to date conversion
...UR_OF_DAY));
Then you can manipulate that with something like:
Calendar now = Calendar.getInstance();
mydate.set(Calendar.YEAR,2009);
mydate.set(Calendar.MONTH,Calendar.FEBRUARY);
mydate.set(Calendar.DAY_OF_MONTH,25);
mydate.set(Calendar.HOUR_OF_DAY,now.get(Calendar.HOUR_OF_DAY));
mydate.set(Cale...
Hook up Raspberry Pi via Ethernet to laptop without router? [closed]
...your laptop (-Y with X-forwarding)
$ssh -Y pi@10.42.0.96
Lo and behold! Now your RPi is connected to your laptop and RPi can share the WiFi connection.
pi@raspberrypi ~ $
Share display & keyboard of your laptop with RPi
Install vncserver on Raspberry Pi
$ sudo apt-get update
$ sudo ap...
Mime type for WOFF fonts?
...ium will recognize
application/x-font-woff
as the mime-type for WOFF. I know this change is now in Chrome beta and if not in stable yet, it shouldn't be too far away.
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How to write LaTeX in IPython Notebook?
...doing, found a better solution with some more searching, IPython notebooks now have a %%latex magic that makes the whole cell Latex without the $$ wrapper for each line.
Refer notebook tour for Rich Display System
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How to store date/time and timestamps in UTC time zone with JPA and Hibernate
...
With Hibernate 5.2, you can now force the UTC time zone using the following configuration property:
<property name="hibernate.jdbc.time_zone" value="UTC"/>
For more details, check out this article.
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