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How to use NULL or empty string in SQL
...pty string. REASON: if there is ONLY whitespace, a single trim will remove all of it. For example, you don't care whether the comparison fails because what remains is "abc" or " abc".
– ToolmakerSteve
Dec 9 '16 at 20:06
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How do I get the SharedPreferences from a PreferenceActivity in Android?
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this, Android provides a simple set of APIs.
Preferences are typically name value pairs. They can be stored as
“Shared Preferences” across various activities in an application (note
currently it cannot be shared across processes). Or it can be
something that needs to be stored spe...
Is it faster to count down than it is to count up?
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Is it really true? and if so does anyone know why?
In ancient days, when computers were still chipped out of fused silica by hand, when 8-bit microcontrollers roamed the Earth, and when your teacher was young (or your teacher's tea...
How to Sort a List by a property in the object
I have a class called Order which has properties such as OrderId , OrderDate , Quantity , and Total . I have a list of this Order class:
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How should strace be used?
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Strace Overview
strace can be seen as a light weight debugger. It allows a programmer / user to quickly find out how a program is interacting with the OS. It does this by monitoring system calls and signals.
Uses
Good for when you don't have source code or don't want to be bothered to real...
Rails: How do I create a default value for attributes in Rails activerecord's model? [duplicate]
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add_column :status, :string, :default => "P"
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OR
You can use a callback, before_save
class Task < ActiveRecord::Base
before_save :default_values
def default_values
self.status ||= 'P' # note self.status = 'P' if self.status.nil? might be safer (per @frontendbeauty)
end
end
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CSS does the width include the padding?
...width: 10em; padding: 2em; border: 1em; }
would be 10em wide.
In contrast, all standards-fearing browsers default to the "content-box" box model. In this model, the width of an element does not include padding or borders. For example:
#foo { width: 10em; padding: 2em; border: 1em; }
will actually be...
Using socket.io in Express 4 and express-generator's /bin/www
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A little different approach to initiate socket.io, it groups all related code in one place:
bin/www
/**
* Socket.io
*/
var socketApi = require('../socketApi');
var io = socketApi.io;
io.attach(server);
socketApi.js
var socket_io = require('socket.io');
var io = socket_io();
var ...
Unstaged changes left after git reset --hard
... It's the * text=auto directive in the gitattributes file. It automatically changes file endings, so the files will automatically be marked as "modified" when you check the status.
– Cody Django
Feb 19 '15 at 22:24
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Abstract Class vs Interface in C++ [duplicate]
...rt interfaces (the "mature approach") instead of C++ classes (this is basically what COM does, but without the burden of COM infrastructure).
I'd use an interface if I want to define a set of rules using which a component can be programmed, without specifying a concrete particular behavior. Classes...