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Should each and every table have a primary key?
I'm creating a database table and I don't have a logical primary key assigned to it. So, I'm thinking about leaving it without a primary key, but I'm feeling a bit guilty about it. Should I?
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The differences between .build, .create, and .create! and when should they be used?
So I've been seeing people using .build , .create , and .create! within their controllers more and more lately. What's the difference from just using .new and passing the param'd object and then .save ? Are there pros and cons? Does using these other methods offer benefits?
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Cross compile Go on OSX?
I am trying to cross-compile a go app on OSX to build binaries for windows and linux. I have read everything what I could find on the net. Closest example that I have found has been published on (apart from many unfinished discussions on go-nuts mailing list):
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How do I adjust the anchor point of a CALayer, when Auto Layout is being used?
...at in layoutSubviews the runtime comes dashing through all the constraints and setting the frames of all the views accordingly.
In other words, the constraints are not magic; they are just a to-do list. layoutSubviews is where the to-do list gets done. And it does it by setting frames.
I can't hel...
What is the difference between an IntentService and a Service? [duplicate]
Can you please help me understand what the difference between an IntentService and a Service is?
8 Answers
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Open a URL in a new tab (and not a new window)
... demonstrate this.)
CSS3 proposed target-new, but the specification was abandoned.
The reverse is not true; by specifying dimensions for the window in the third argument of window.open(), you can trigger a new window when the preference is for tabs.
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What is the difference between map and flatMap and a good use case for each?
Can someone explain to me the difference between map and flatMap and what is a good use case for each?
16 Answers
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“static const” vs “#define” vs “enum”
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It depends on what you need the value for. You (and everyone else so far) omitted the third alternative:
static const int var = 5;
#define var 5
enum { var = 5 };
Ignoring issues about the choice of name, then:
If you need to pass a pointer around, you must use (1).
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'Must Override a Superclass Method' Errors after importing a project into Eclipse
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Eclipse is defaulting to Java 1.5 and you have classes implementing interface methods (which in Java 1.6 can be annotated with @Override, but in Java 1.5 can only be applied to methods overriding a superclass method).
Go to your project/IDE preferences and s...
Why does Java's hashCode() in String use 31 as a multiplier?
...to Joshua Bloch's Effective Java (a book that can't be recommended enough, and which I bought thanks to continual mentions on stackoverflow):
The value 31 was chosen because it is an odd prime. If it were even and the multiplication overflowed, information would be lost, as multiplication by 2 i...