大约有 7,000 项符合查询结果（耗时：0.0211秒） [XML]
What are the use cases for selecting CHAR over VARCHAR in SQL?
.... So (assuming you are using a one-byte character set) storing the word "FooBar"
CHAR(6) = 6 bytes (no overhead)
VARCHAR(100) = 8 bytes (2 bytes of overhead)
CHAR(10) = 10 bytes (4 bytes of waste)
The bottom line is CHAR can be faster and more space-efficient for data of relatively the same leng...
When should static_cast, dynamic_cast, const_cast and reinterpret_cast be used?
...constness.
Another example is when you want to implement T& SomeClass::foo() as well as const T& SomeClass::foo() const. To avoid code duplication, you can apply const_cast to return value of one function from another.
reinterpret_cast
This basically says that take these bytes at this me...
REST, HTTP DELETE and parameters
...urn a 303 See Other. And just to counter the obvious objection to this, /foo.xml and /foo.json are two different resources.
– Darrel Miller
Mar 30 '10 at 23:41
...
Switch statement fallthrough in C#?
...ect.
And when you think about it, code like this:
switch(x)
{
case 1:
foo();
/* FALLTHRU */
case 2:
bar();
break;
}
Is adding something to make the fall-through explicit in the code, it's just not something that can be detected (or whose absence can be detected) by the compiler.
A...
RESTful Alternatives to DELETE Request Body
...strings. The query string is part of the URI. Sending a DELETE request to /foo?123 means you are deleting a different resource than if you were to send DELETE to /foo?456.
– Nicholas Shanks
Jan 25 '16 at 17:38
...
Python read-only property
...ort read_only_properties
In [2]: @read_only_properties('a')
...: class Foo:
...: def __init__(self, a, b):
...: self.a = a
...: self.b = b
...:
In [3]: f=Foo('explodes', 'ok-to-overwrite')
In [4]: f.b = 5
In [5]: f.a = 'boom'
--------------------------...
If Python is interpreted, what are .pyc files?
... in different languages, with different acceptable translations, levels of footnotes and other annotations) -- however, those books are perfectly well allowed to differ in a myriad of aspects that are not considered fundamental -- kind of binding, color of binding, font(s) used in the printing, illu...
What is the difference between RDF and OWL? [closed]
...ou can describe that some resource is an instance of a class:
<http://foo.com/anna> rdf:type <http://foo.com/teacher>
So the RDF vocabulary has terms that are targeting basic descriptions of class instances and some other descriptions (like the triple statement definition, or the pr...
The new keyword “auto”; When should it be used to declare a variable type? [duplicate]
...unwanted implicit conversions in initialisations. Generally, the statement Foo x = y; will perform an implicit conversion if y isn’t of type Foo and an implicit conversion exists. This is the reason to avoid having implicit conversions in the first place. Unfortunately, C++ has much too many of th...
What is an IndexOutOfRangeException / ArgumentOutOfRangeException and how do I fix it?
...your parameters are T[] you're safe about custom lower bound arrays:
void foo<T>(T[] array) { }
void test() {
// This will throw InvalidCastException, cannot convert Int32[] to Int32[*]
foo((int)Array.CreateInstance(typeof(int), new int[] { 1 }, new int[] { 1 }));
}
Validate Parame...