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How important is the order of columns in indexes?
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See how restricting on A first, as your first column eliminates more results than restricting on your second column first? It's easier if you picture how the index must be traversed across, column 1, then column 2, etc...you see that lopping off most of the results in the fist pass makes ...
What is the difference between a web API and a web service?
Is there any difference between a web API and a web service ? Or are they one and the same ?
12 Answers
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How do I use extern to share variables between source files?
I know that global variables in C sometimes have the extern keyword. What is an extern variable? What is the declaration like? What is its scope?
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How to write an async method with out parameter?
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You can't have async methods with ref or out parameters.
Lucian Wischik explains why this is not possible on this MSDN thread: http://social.msdn.microsoft.com/Forums/en-US/d2f48a52-e35a-4948-844d-828a1a6deb74/why-async-methods-cannot-have-ref-or-out-parameters
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Filling a DataSet or DataTable from a LINQ query result set
...b service? Usually, from the business tier, I can return a typed DataSet or DataTable which can be serialized for transport over ASMX.
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Modelling an elevator using Object-Oriented Analysis and Design [closed]
...seem to be commonly-used in interviews and classes when it comes to object-oriented design and analysis. This is one of them; unfortunately, my OOP professor in college never actually gave an answer to it, and so I've been wondering.
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Set every cell in matrix to 0 if that row or column contains a 0
...the beginning depend on squares in the end. Maybe my 2nd pass can be made more efficient...
import pprint
m = [[1, 0, 1, 1, 0],
[0, 1, 1, 1, 0],
[1, 1, 1, 1, 1],
[1, 0, 1, 1, 1],
[1, 1, 1, 1, 1]]
N = len(m)
### pass 1
# 1 rst line/column
c = 1
for i in range(N):
c &...
Using i and j as variables in Matlab
... i and j are both functions denoting the imaginary unit:
http://www.mathworks.co.uk/help/matlab/ref/i.html
http://www.mathworks.co.uk/help/matlab/ref/j.html
So a variable called i or j will override them, potentially silently breaking code that does complex maths.
Possible solutions include usi...
Difference between DateTime and Time in Ruby
... the difference between DateTime and Time classes in Ruby and what factors would cause me to choose one or the other?
7...
What's the purpose of using braces (i.e. {}) for a single-line if or loop?
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Let's attempt to also modify i when we increment j:
int j = 0;
for (int i = 0 ; i < 100 ; ++i)
if (i % 2 == 0)
j++;
i++;
Oh no! Coming from Python, this looks ok, but in fact it isn't, as it's equivalent to:
int j = 0;
for (int i = 0 ; i < 100 ; ++i)
if (i...