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How to UPSERT (MERGE, INSERT … ON DUPLICATE UPDATE) in PostgreSQL?
...e.
If you're on 9.5 and don't need to be backward-compatible you can stop reading now.
9.4 and older:
PostgreSQL doesn't have any built-in UPSERT (or MERGE) facility, and doing it efficiently in the face of concurrent use is very difficult.
This article discusses the problem in useful detail.
In g...
Python (and Python C API): __new__ versus __init__
...behavior of __new__. We pass cls explicitly to __new__ because, as you can read here __new__ always requires a type as its first argument. It then returns an instance of that type. So we aren't returning an instance of the superclass -- we're returning an instance of cls. In this case, it's just the...
Why not be dependently typed?
...on of the value and type levels, so you can parametrize values on types (already possible with type classes and parametric polymorphism in Haskell) and you can parametrize types on values (not, strictly speaking, possible yet in Haskell, although DataKinds gets very close).
Edit: Apparently, from ...
How to wait for all goroutines to finish without using time.Sleep?
...ollect and process the results in the second for loop (as soon as they are ready)
– andras
Aug 13 '13 at 22:55
5
...
How to update PATH variable permanently from Windows command line?
... modifying system PATH. It just needs a simple C++ app with a few registry reads and writes, followed by a SendMessage. Set the requestedExecutionLevel to requireAdministrator in the app manifest.
– David Heffernan
Dec 2 '11 at 15:56
...
Python Infinity - Any caveats?
...result in inf or NaN, I just wanted to make it clear to others that may be reading through the comments, that 1/float('infinity')==0.0 is true; for, as you are approaching infinity, the result of the division approaches 0. I know it's just basic calculus, but I wanted to be sure those reading under...
Loading basic HTML in Node.js
...cleanest though.
var http = require('http'),
fs = require('fs');
fs.readFile('./index.html', function (err, html) {
if (err) {
throw err;
}
http.createServer(function(request, response) {
response.writeHeader(200, {"Content-Type": "text/html"});
...
How can I make a weak protocol reference in 'pure' Swift (without @objc)
...ss SomeClass {
weak var delegate: MyClassDelegate?
}
Further Study
Reading the following articles is what helped me to understand this much better. They also discuss related issues like the unowned keyword and the strong reference cycles that happen with closures.
Delegate documentation
Sw...
Set Additional Data to highcharts series
...; you can use Array.find. It's not supported by IE, but you're using ES6 already (const) and MS stopped supporting IE in 2016.
– Dan Dascalescu
Feb 17 '18 at 4:51
...
What strategies and tools are useful for finding memory leaks in .NET?
...ass ParentObject
Private mRelatedObject as New CRelatedObject
public Readonly property RelatedObject() as CRelatedObject
get
mRelatedObject.getWithID(RelatedObjectID)
return mRelatedObject
end get
end property
End class
We found that the above system created ...