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Are foreign keys really necessary in a database design?
As far as I know, foreign keys (FK) are used to aid the programmer to manipulate data in the correct way. Suppose a programmer is actually doing this in the right manner already, then do we really need the concept of foreign keys?
...
How to call any method asynchronously in c#
...ay to fire-and-forget for async jobs:
using System.Threading.Tasks;
...
void Foo(){}
...
new Task(Foo).Start();
If you have methods to call that take parameters, you can use a lambda to simplify the call without having to create delegates:
void Foo2(int x, string y)
{
return;
}
...
new Task(...
The difference between try/catch/throw and try/catch(e)/throw e
...e) { ... }
are similar in that both will catch every exception thrown inside the try block (and, unless you are simply using this to log the exceptions, should be avoided). Now look at these:
try { ... }
catch ()
{
/* ... */
throw;
}
try { ... }
catch (Exception e)
{
/* ... */
th...
Validating an XML against referenced XSD in C#
...hat to your XmlReader when you create it. Then you can subscribe to the ValidationEventHandler in the settings to receive validation errors. Your code will end up looking like this:
using System.Xml;
using System.Xml.Schema;
using System.IO;
public class ValidXSD
{
public static void Main()
...
Custom error pages on asp.net MVC3
... }
public ActionResult Http403()
{
return Content("Forbidden", "text/plain");
}
}
and then I subscribe for the Application_Error in Global.asax and invoke this controller:
protected void Application_Error()
{
var exception = Server.GetLastError();
var httpException...
How to redirect output of an entire shell script within the script itself?
...e output of a Bourne shell script to somewhere, but with shell commands inside the script itself?
5 Answers
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How to return smart pointers (shared_ptr), by reference or by value?
...
Return smart pointers by value.
As you've said, if you return it by reference, you won't properly increment the reference count, which opens up the risk of deleting something at the improper time. That alone should be enough reason to not return by reference. Interface...
Decreasing height of bootstrap 3.0 navbar
...ent for toggling -->
<div class="collapse navbar-collapse" id="bs-example-navbar-collapse-8">
<ul class="nav navbar-nav">
<li class="active"><a href="#">Home</a></li>
<li><a href="#">Link&l...
What character encoding should I use for a HTTP header?
...s gave up and specified that in the headers there is no useful encoding besides ASCII:
Historically, HTTP has allowed field content with text in the
ISO-8859-1 charset [ISO-8859-1], supporting other charsets only
through use of [RFC2047] encoding. In practice, most HTTP header
fi...
Efficient way to apply multiple filters to pandas DataFrame or Series
... col2
1 1 11
If you want to write helper functions for this, consider something along these lines:
In [14]: def b(x, col, op, n):
return op(x[col],n)
In [15]: def f(x, *b):
return x[(np.logical_and(*b))]
In [16]: b1 = b(df, 'col1', ge, 1)
In [17]: b2 = b(df, ...