大约有 40,000 项符合查询结果（耗时：0.0561秒） [XML]
How to change a nullable column to not nullable in a Rails migration?
...lse, <put a default value here> )
# change_column(:users, :admin, :string, :default => "")
end
Changing a column with NULL values in it to not allow NULL will cause problems. This is exactly the type of code that will work fine in your development setup and then crash when you try to d...
How do I get a YouTube video thumbnail from the YouTube API?
...5 (5) {
["default"]=>
object(stdClass)#6 (3) {
["url"]=>
string(46) "https://i.ytimg.com/vi/T0Jqdjbed40/default.jpg"
["width"]=>
int(120)
["height"]=>
int(90)
}
["medium"]=>
object(stdClass)#7 (3) {
["url"]=>
string(48) "https://i.ytimg.com...
C# switch statement limitations - why?
...t believe the compiler generates constant-time branching when switching on strings either.
– Drew Noakes
Dec 3 '10 at 21:29
...
How to get the IP address of the server on which my C# application is running on?
...only thing I would change would be to change this:
if (ip.AddressFamily.ToString() == "InterNetwork")
to this:
if (ip.AddressFamily == AddressFamily.InterNetwork)
There is no need to ToString an enumeration for comparison.
...
What is the best django model field to use to represent a US dollar amount?
...
I think this example is correct almost to all currencies. To represent currencies as Bitcoin, I think is much better to use an integer field to save the amount in satoshis, and then show it to the final user in the representation that you want (BTC, mBTC, etc)
...
Logging framework incompatibility
...ject[] p5):
SLF4J 1.5.11:
LocationAwareLogger.log ( org.slf4j.Marker p1, String p2, int p3,
String p4, Throwable p5 )
SLF4J 1.6.0:
LocationAwareLogger.log ( org.slf4j.Marker p1, String p2, int p3,
String p4, Object[] p5, Throwable p6 )
See c...
What is the meaning of “this” in Java?
... System.out.println(this); // refers to this entire object
}
public String toString() {
return "MyThisTest a=" + a; // refers to the field a
}
}
Then calling frobnicate() on new MyThisTest() will print
1
42
MyThisTest a=42
So effectively you use it for multiple things:
clarify ...
How to insert a text at the beginning of a file?
...dd a line at the beginning of a file, you need to add \n at the end of the string in the best solution above.
The best solution will add the string, but with the string, it will not add a line at the end of a file.
sed -i '1s/^/your text\n/' file
...
Why must wait() always be in synchronized block
...d look something along the lines below
class BlockingQueue {
Queue<String> buffer = new LinkedList<String>();
public void give(String data) {
buffer.add(data);
notify(); // Since someone may be waiting in take!
}
public String take() t...
How to show the “Are you sure you want to navigate away from this page?” when changes committed?
... consistently by all browsers. It should be a function reference and not a string (as the original answer stated) but that will work in older browsers because the check for most of them appears to be whether anything is assigned to onbeforeunload (including a function that returns null).
You set wi...