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Why use 'virtual' for class properties in Entity Framework model definitions?
...any navigation properties are not relevant at first. i.e. In a customer / Orders scenario, you do not have to wait until the moment an order is processed to create a customer. You can, but if you had a multi-stage process to achieve this, you might find the need to persist the customer data for la...
Difference between EXISTS and IN in SQL?
... will tell you whether a query returned any results. e.g.:
SELECT *
FROM Orders o
WHERE EXISTS (
SELECT *
FROM Products p
WHERE p.ProductNumber = o.ProductNumber)
IN is used to compare one value to several, and can use literal values, like this:
SELECT *
FROM Orders
WHERE Produ...
What is the minimum valid JSON?
... to be one such example which only accepts objects and arrays as the root. PHP, on the other hand, specifically adds the exception that "it will also encode and decode scalar types and NULL".
share
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What is the curiously recurring template pattern (CRTP)?
...
};
template <class T>
T* Singleton<T>::p = nullptr;
Now, in order to make an arbitrary class A a singleton you should do this
class A: public Singleton<A>
{
//Rest of functionality for class A
};
So you see? The singleton template assumes that its specialization for any ty...
How to concatenate and minify multiple CSS and JavaScript files with Grunt.js (0.3.x)
...n array to explicitly define which files you want to concatenate and their order, or change the structure of your project.
If doing the latter, you could put all your sources under ./src and your built files under ./dest
src
├── css
│ ├── 1.css
│ ├── 2.css
│ ...
How to get these two divs side-by-side?
..._div_1, #parent_div_2, #parent_div_3 {
width: 100px;
height: 100px;
border: 1px solid red;
margin-right: 10px;
float: left;
}
.child_div_1 {
float: left;
margin-right: 5px;
}
Check working example at http://jsfiddle.net/c6242/1/
...
TypeError: method() takes 1 positional argument but 2 were given
...o understand that only instance methods take self as the first argument in order to refer to the instance.
In case the method is Static you don't pass self, but a cls argument instead (or class_).
Please see an example below.
class City:
country = "USA" # This is a class level attribute which wi...
Android: How can I validate EditText input?
...
In order to reduce the verbosity of the validation logic I have authored a library for Android. It takes care of most of the day to day validations using Annotations and built-in rules. There are constraints such as @TextRule, @...
What are Scala context and view bounds?
... view bounds in the standard library (before Scala 2.8.0, anyway), is with Ordered, like this:
def f[A <% Ordered[A]](a: A, b: A) = if (a < b) a else b
Because one can convert A into an Ordered[A], and because Ordered[A] defines the method <(other: A): Boolean, I can use the expression a...
How do you express binary literals in Python?
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