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Create unique constraint with null columns
...en help to maintain all three indexes (the two partial ones and a total on top).
Aside: I advise not to use mixed case identifiers in PostgreSQL.
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Is gcc std::unordered_map implementation slow? If so - why?
... showLowRepImageUploadWarning: true,
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brandingHtml: "Powered by \u003ca href=\"https://imgur.com/\"\u003e\u003csvg cla...
Adding a Method to an Existing Object Instance
..._.A'> - m
<class '__main__.A'> - m
Now, I'm not sure out of the top of my head why the last line is printed twice, but still it's clear what's going on there.
Now, what the default __getattribute__ does is that it checks if the attribute is a so-called descriptor or not, i.e. if it imple...
How to avoid isset() and empty()
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For those interested, I have expanded this topic into a small article, which provides the below information in a somewhat better structured form: The Definitive Guide To PHP's isset And empty
IMHO you should think about not just making the app "E_NOTICE compatible"...
How to do a FULL OUTER JOIN in MySQL?
...f a UNION as meaning "run both of these queries, then stack the results on top of each other"; some of the rows will come from the first query and some from the second.
It should be noted that a UNION in MySQL will eliminate exact duplicates: Tim would appear in both of the queries here, but the re...
Calling clojure from java
Most of the top google hits for "calling clojure from java" are outdated and recommend using clojure.lang.RT to compile the source code. Could you help with a clear explanation of how to call Clojure from Java assuming you have already built a jar from the Clojure project and included it in the cl...
What is the difference between LL and LR parsing?
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The LL uses top-down, while the LR uses bottom-up approach.
If you parse a progamming language:
The LL sees a source code, which contains functions, which contains expression.
The LR sees expression, which belongs to functions, which ...
Node.js and CPU intensive requests
...bout it at that link. In fact, if you just rip off the example code at the top of that link you will get yourself 95% of the way there.
The other way to structure this is to set up a job queue and send big compute tasks over the queue. Note that there is a lot of overhead associated with the IPC fo...
MySQL: @variable vs. variable. What's the difference?
...lock in the procedure, unlike mySQL which requires all the DECLAREs at the top.
While good on the command line, I feel using the "set = @variable" within stored procedures in mySQL is risky. There is no scope and variables live across scope boundaries. This is similar to variables in JavaScript b...
Enable access control on simple HTTP server
...hich will set the CORS header for every response.
With the shebang at the top, make the file executable and put it into your PATH, and you can just run it using simple-cors-http-server.py too.
Python 3 solution
Python 3 uses SimpleHTTPRequestHandler and HTTPServer from the http.server module to r...