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How do you effectively model inheritance in a database?
...s only the different elements.
So for example:
class Person {
public int ID;
public string FirstName;
public string LastName;
}
class Employee : Person {
public DateTime StartDate;
}
Would result in tables like:
table Person
------------
int id (PK)
string firstname
string last...
Link to add to Google calendar
...
To convert to the datetime format: (new Date()).toISOString().replace(/-|:|\.\d\d\d/g,"");
– Trantor Liu
Dec 30 '14 at 10:36
...
Is there a constraint that restricts my generic method to numeric types?
...Hejlsberg has described the reasons for not implementing the feature in an interview with Bruce Eckel:
And it's not clear that the added complexity is worth the small yield that you get. If something you want to do is not directly supported in the constraint system, you can do it with a factory ...
Best practices for circular shift (rotate) operations in C++
...apted it to rotate by the width of the type (using fixed-width types like uint32_t).
#include <stdint.h> // for uint32_t
#include <limits.h> // for CHAR_BIT
// #define NDEBUG
#include <assert.h>
static inline uint32_t rotl32 (uint32_t n, unsigned int c)
{
const unsigned int...
How can I initialize base class member variables in derived class constructor?
... B (or any subclass of A) to initialize them:
class A
{
protected:
A(int a, int b) : a(a), b(b) {} // Accessible to derived classes
// Change "protected" to "public" to allow others to instantiate A.
private:
int a, b; // Keep these variables private in A
};
class B : public A
{
publ...
Does Parallel.ForEach limit the number of active threads?
...of threads, but that number is calculated based on an algorithm that takes into account and appears to continually monitor the work done by the threads it's allocating to the ForEach. So if the body part of the ForEach calls out to long running IO-bound/blocking functions which would leave the threa...
Programmatically obtain the Android API level of a device?
...obtain API level programatically by the system constant (Build.VERSION.SDK_INT). For example you can run some piece of code which requires newer API in the following way (it will execute if the current device's API level is at least 4)
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.DONUT) {
}...
Increment value in mysql update query
... in this query uses an arithmetic operator (the plus symbol +), MySQL will convert any strings in the expression to numbers.
To demonstrate, the following will produce the result 6:
SELECT ' 05.05 '+'.95';
String concatenation in MySQL requires the CONCAT() function so there is no ambiguity here...
Can I call a constructor from another constructor (do constructor chaining) in C++?
... syntax is slightly different from C#:
class Foo {
public:
Foo(char x, int y) {}
Foo(int y) : Foo('a', y) {}
};
C++03: No
Unfortunately, there's no way to do this in C++03, but there are two ways of simulating this:
You can combine two (or more) constructors via default parameters:
class...
What are forward declarations in C++?
... to contain very clever logic to try and work out which 'add' you actually intended to call, when the 'add' function may live in a different object file the linker is joining with the one that uses add to produce a dll or exe. It's possible that the linker may get the wrong add. Say you wanted to us...