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Delete everything in a MongoDB database
I'm doing development on MongoDB. For totally non-evil purposes, I sometimes want to blow away everything in a database—that is, to delete every single collection, and whatever else might be lying around, and start from scratch. Is there a single line of code that will let me do this? Bonus points...
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This, along with all the other conditional comments solutions, will not detect IE 10 / IE 11
– Lloyd Banks
Oct 5 '13 at 2:23
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What is the best way to uninstall gems from a rails3 project?
I installed all of my gems using bundler via the Gemfile. I thought (mistakenly) that if I deleted a gem from my Gemfile and ran 'bundle install' that the deleted gems would be uninstalled. I've looked at the bundler help file and, so far as I can tell, it does not have a way to uninstall gems.
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Select n random rows from SQL Server table
...the key scan of values plus the join cost, which on a large table with a small percentage selection should be reasonable.
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How do you use “git --bare init” repository?
...ush) from another repository.
Note that in this case you'll need to first allow people to push to your repository. When inside test_repo.git, do
git config receive.denyCurrentBranch ignore
Community edit
git init --bare --shared=group
As commented by prasanthv, this is what you want if you ar...
Using CSS for a fade-in effect on page load
Can CSS transitions be used to allow a text paragraph to fade-in on page load?
3 Answers
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What's the difference between nohup and ampersand
... doesn't (except the shell is confgured that way or doesn't send SIGHUP at all).
Normally, when running a command using & and exiting the shell afterwards, the shell will terminate the sub-command with the hangup signal (kill -SIGHUP <pid>). This can be prevented using nohup, as it catche...
How does Apple find dates, times and addresses in emails?
...ay be wrong). On the other hand I'd except the naiive approach of encoding all common formats to perform way better (possibly 0.99+ given that the most frequent formats will never be missed) and to be faster to implement + at runtime.
– b.buchhold
Feb 25 '12 at...
SQLite UPSERT / UPDATE OR INSERT
...answer. Starting from SQLIte 3.24.0, released on June 4, 2018, there is finally a support for UPSERT clause following PostgreSQL syntax.
INSERT INTO players (user_name, age)
VALUES('steven', 32)
ON CONFLICT(user_name)
DO UPDATE SET age=excluded.age;
Note: For those having to use a vers...
Computational complexity of Fibonacci Sequence
...ll have depth n and intuitively figure out that this function is asymptotically O(2n). You can then prove your conjecture by induction.
Base: n = 1 is obvious
Assume T(n-1) = O(2n-1), therefore
T(n) = T(n-1) + T(n-2) + O(1) which is equal to
T(n) = O(2n-1) + O(2n-2) + O(1) = O(2n)
However, as ...