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Running PostgreSQL in memory only
...ils from a properties file, build target properties, environment variable, etc.
It's safe to use an existing PostgreSQL instance you already have databases you care about in, so long as the user you supply to your unit tests is not a superuser, only a user with CREATEDB rights. At worst you'll crea...
What is SELF JOIN and when would you use it? [duplicate]
...yee as boss
from emptable e, emptable b
where e.manager_id = b.empolyee_id
order by 1
It's basically used where there is any relationship between rows stored in the same table.
employees.
multi-level marketing.
machine parts.
And so on...
...
Linux error while loading shared libraries: cannot open shared object file: No such file or director
...ies found in the directories specified on the command
line, in the file /etc/ld.so.conf, and in the trusted directories
(/lib and /usr/lib).
Usually your package manager will take care of this when you install a new library, but not always, and it won't hurt to run ldconfig even if that is not...
How to retrieve an element from a set without removing it?
... since iteration seems to sort the elements. I would prefer them in random order...
– Daren Thomas
Sep 12 '08 at 20:17
10
...
Why were pandas merges in python faster than data.table merges in R in 2012?
....table has time series merge in mind. Two aspects to that: i) multi column ordered keys such as (id,datetime) ii) fast prevailing join (roll=TRUE) a.k.a. last observation carried forward.
I'll need some time to confirm as it's the first I've seen of the comparison to data.table as presented.
UPD...
Laravel - Eloquent or Fluent random row
...
Laravel >= 5.2:
User::inRandomOrder()->get();
or to get the specific number of records
// 5 indicates the number of records
User::inRandomOrder()->limit(5)->get();
// get one random record
User::inRandomOrder()->first();
or using the random ...
Vertically align an image inside a div with responsive height
...ation to the first-child and our element (the image) both.
3) Finally, in order to remove the white space character between inline(-block) elements, we could set the font size of the parent to zero by font-size: 0;.
Note: I used Nicolas Gallagher's image replacement technique in the following.
Wh...
What is the difference between “INNER JOIN” and “OUTER JOIN”?
...great and excellent explanation. but why in column b the values are not in order? i.e it is 6,5 not as 5,6?
– Ameer
Mar 4 '13 at 8:39
...
Where can I learn how to write C code to speed up slow R functions? [closed]
...simpler code, less boilerplate, no PROTECT/UNPROTECT, no memory management etc pp. Doug Bates just yesterday stated that he finds C++ and Rcpp to be much more like writing R than writing C++. YMMV and all that.
share
...
Node.js: what is ENOSPC error and how to solve?
...d to avoid ENOSPC:
echo fs.inotify.max_user_watches=524288 | sudo tee -a /etc/sysctl.conf && sudo sysctl -p
For Arch Linux add this line to /etc/sysctl.d/99-sysctl.conf:
fs.inotify.max_user_watches=524288
Then execute:
sysctl --system
This will also persist across reboots.
Technic...