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How do SQL EXISTS statements work?

...hen tries to match this 'true/false' condition with outerquery." is what really cleared it up for me, I keep thinking that's how subqueries work (and many times they do), but what you said makes sense because the subquery relies on the outer query and therefore must be executed once per row ...
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What is the JavaScript version of sleep()?

...e 2009 when this question was asked, JavaScript has evolved significantly. All other answers are now obsolete or overly complicated. Here is the current best practice: function sleep(ms) { return new Promise(resolve => setTimeout(resolve, ms)); } async function demo() { console.log...
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Do I need elements in persistence.xml?

...k at the Chapter2. Setup and configuration too for more details. EDIT: Actually, If you don't mind not being spec compliant, Hibernate supports auto-detection even in Java SE. To do so, add the hibernate.archive.autodetection property: <persistence-unit name="eventractor" transaction-type="RESOUR...
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Find the last element of an array while using a foreach loop in PHP

...x compared to this one. I have not ran any tests but I guess this answer shall be faster as it is not extracting array of keys.This shall have O(1) speed – Vaibhav Kamble Mar 20 '09 at 7:09 ...
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How can I determine the URL that a local Git repository was originally cloned from?

...re several forks on GitHub, and I neglected to note which one I took originally. How can I determine which of those forks I pulled? ...
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rvm installation not working: “RVM is not a function”

I just installed RVM, but can't make it work. I have such line at the end of my .profile file: 21 Answers ...
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Optimal number of threads per core

... want to run some process in the minimum amount of time. The process is ideally parallelizable, so I can run chunks of it on an infinite number of threads and each thread takes the same amount of time. ...
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When to choose checked and unchecked exceptions

...eople misunderstand what this means. Predictable but unpreventable: The caller did everything within their power to validate the input parameters, but some condition outside their control has caused the operation to fail. For example, you try reading a file but someone deletes it between the time ...
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Why am I suddenly getting a “Blocked loading mixed active content” issue in Firefox?

... main page is served over HTTPS. When an HTTPS page has HTTP content, we call that content “mixed”. The webpage that the user is visiting is only partially encrypted, since some of the content is retrieved unencrypted over HTTP. The Mixed Content Blocker blocks certain HTTP requests on HTTPS p...
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Display string as html in asp.net mvc view

...n I am displaying it on views, it is displayed as simple string containing all tags. I tried to use Html helper to encode/decode to display it properly, but it is not working. ...