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Can I have multiple primary keys in a single table?
...e can have a Composite Primary Key which is a primary key made from two or more columns. For example:
CREATE TABLE userdata (
userid INT,
userdataid INT,
info char(200),
primary key (userid, userdataid)
);
Update: Here is a link with a more detailed description of composite primary keys.
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Detect HTTP or HTTPS then force HTTPS in JavaScript
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Position of least significant bit that is set
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What is the difference between Ruby 1.8 and Ruby 1.9
..._CHAR
end
end
unpack('U*').map {|n| n.xchr(escape)}.join
BasicObject More Brutal Than BlankSlate
Ruby 1.9
irb(main):001:0> class C < BasicObject; def f; Math::PI; end; end; C.new.f
NameError: uninitialized constant C::Math
Ruby 1.8.6
irb(main):001:0> require 'blankslate'
=> tr...
How can I disable ARC for a single file in a project?
...(e.g., in unit tests and mock objects) where the rules of ARC are a little more fragile right now. I recall hearing that there was a way to disable ARC on a per-file basis, though I have been unable to find this option.
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How do I convert a String to an InputStream in Java?
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Is there a TRY CATCH command in Bash
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Concat all strings inside a List using LINQ
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What is the best way to trigger onchange event in react js
... The input logic in React now dedupe's change events so they don't fire
more than once per value. It listens for both browser onChange/onInput
events as well as sets on the DOM node value prop (when you update the
value via javascript). This has the side effect of meaning that if you
update...
In HTML5, should the main navigation be inside or outside the element?
...at's where navigation often goes, but it's not set in stone.
You can read more about it at HTML5 Doctor.
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