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How to add column if not exists on PostgreSQL?
...statement:
DO $$
BEGIN
BEGIN
ALTER TABLE <table_name> ADD COLUMN <column_name> <column_type>;
EXCEPTION
WHEN duplicate_column THEN RAISE NOTICE 'column <column_name> already exists in <table_name>.';
END;
END;
$$
...
From inside of a Docker container, how do I connect to the localhost of the machine?
...as described in qoomon's answer.
2020-01: some progress has been made. If all goes well, this should land in Docker 20.04
TLDR
Use --network="host" in your docker run command, then 127.0.0.1 in your docker container will point to your docker host.
Note: This mode only works on Docker for Linux...
Preventing scroll bars from being hidden for MacOS trackpad users in WebKit/Blink
...
One thing to mention is that, in my testing and a really old comment by someone else it seems you can't have an always-on scrollbar AND the momentum-like scrolling that people are used to with iOS. Doing the momentum-scrolling CSS caused my custom scrollbars to disappear.
...
Force to open “Save As…” popup open at text link click for PDF in HTML
... the time of this comment, I've tested it on Chrome, Opera, Edge, Mozilla. All latest. Is working on all except on Mozilla.
– S.I.
Sep 29 '17 at 5:07
7
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Fastest Way to Serve a File Using PHP
...erywhere.
Using the X-SendFile header
As documented by others it's actually the best way. The basis is that you do your access control in php and then instead of sending the file yourself you tell the web server to do it.
The basic php code is :
header("X-Sendfile: $file_name");
header("Conten...
SSL Error: CERT_UNTRUSTED while using npm command
I am trying to install express framework using npm command but getting following error.
7 Answers
...
How to iterate for loop in reverse order in swift?
... an array with one trillion Ints!
Test:
var count = 0
for i in lazy(1...1_000_000_000_000).reverse() {
if ++count > 5 {
break
}
println(i)
}
For Swift 2.0 in Xcode 7:
for i in (1...10).reverse() {
print(i)
}
Note that in Swift 2.0, (1...1_000_000_000_000).reverse(...
Is git's semi-secret empty tree object reliable, and why is there not a symbolic name for it?
...0 +0000" GIT_COMMITTER_DATE="Thu, 01 Jan 1970 00:00:00 +0000" git commit --allow-empty -m 'Initial commit'
Will give you:
(See the tree SHA1?)
You can even rebase your existing history on top of that empty commit (see "git: how to insert a commit as the first, shifting all the others?")
In bo...
Optimise PostgreSQL for fast testing
...ta-integrity-protection and crash-safety stuff, giving it permission to totally trash your data if you lose power or have an OS crash.
Needless to say, you should never enable fsync=off in production unless you're using Pg as a temporary database for data you can re-generate from elsewhere. If and ...
Generate a random double in a range
...
This is generally correct, but beware of its limits. If you do double rangeMax= Double.MAX_VALUE; and double rangeMin= -rangeMax; you will always get an infinite value in return. You might want to check for Double.valueOf(rangeMax-range...