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Message Queue vs Message Bus — what are the differences?

And are there any? To me, MB knows both subscribers and publishers and acts as a mediator, notifying subscribers on new messages (effectively a "push" model). MQ, on the other hand, is more of a "pull" model, where consumers pull messages off a queue. ...
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A migration to add unique constraint to a combination of columns

...uble tap on an api heavy app) I have two identical records in my DB right now and the model has the validation.. – baash05 Mar 17 '15 at 1:26 6 ...
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What is the point of a private pure virtual function?

... virtual void SetState( int var, int val ) {/*some implementation*/} }; Now let's assume you want to create a derived class and you need to provide a new implementation only for the method, that takes two ints as arguments. class MyTurbochargedV8 : public Engine { public: // To prevent SetSt...
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What's the role of GetHashCode in the IEqualityComparer in .NET?

...r.GetHashCode methods are used instead of the methods on the Key objects. Now to explain why both methods are necessary, consider this example: BoxEqualityComparer boxEqC = new BoxEqualityComparer(); Dictionary<Box, String> boxes = new Dictionary<Box, string>(boxEqC); Box redBox = ...
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What exactly do the Vagrant commands do?

..., when you execute vagrant ssh to ssh into VM. It is utilizing it's well known ssh key. The information on this key is provided by vagrant ssh-config. This is useful in case you want to change the well know key to your own private key and prepare boxes to use that. Also some times, you may want t...
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Why does changing 0.1f to 0 slow down performance by 10x?

... @s73v3r That's a very good question. Now that I look at the assembly, not even + 0.0f gets optimized out. If I had to guess, it could be that + 0.0f would have side-effects if y[i] happened to be a signalling NaN or something... I could be wrong though. ...
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What's is the difference between include and extend in use case diagram?

...re sometimes” is a very common misconception which has almost taken over now as the de-facto meaning. Here’s a correct approach (in my view, and checked against Jacobson, Fowler, Larmen and 10 other references). Relationships are dependencies The key to Include and extend use case relationshi...
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Truncating long strings with CSS: feasible yet?

... Update: text-overflow: ellipsis is now supported as of Firefox 7 (released September 27th 2011). Yay! My original answer follows as a historical record. Justin Maxwell has cross browser CSS solution. It does come with the downside however of not allowing the ...
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How to find time complexity of an algorithm

...y 2. For this reason, we drop all but the largest terms for large N. So, now we have gone from 2N + 2 to 2N. Traditionally, we are only interested in performance up to constant factors. This means that we don't really care if there is some constant multiple of difference in performance when N i...
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Why should you use an ORM? [closed]

...aking data access more abstract and portable. ORM implementation classes know how to write vendor-specific SQL, so you don't have to. share | improve this answer | follow ...