大约有 7,000 项符合查询结果（耗时：0.0438秒） [XML]
When and why are database joins expensive?
I'm doing some research into databases and I'm looking at some limitations of relational DBs.
7 Answers
...
How would Git handle a SHA-1 collision on a blob?
... having the same SHA-1 as another that is already in your repository. Question is, how would Git handle this? Simply fail? Find a way to link the two blobs and check which one is needed according to the context?
...
How do I scroll the UIScrollView when the keyboard appears?
... to change the contentInset of the UIScrollView. It is a very elegant solution, because you do not have to mess with the contentSize.
Following code is copied from the Keyboard Programming Guide, where the handling of this issue is explained. You should have a look into it.
// Call this method som...
Rounded UIView using CALayers - only some corners - How?
In my application - there are four buttons named as follows:
14 Answers
14
...
How can I restart a Java application?
How can I restart a Java AWT application? I have a button to which I have attached an event handler. What code should I use to restart the application?
...
how to stop browser back button using javascript
...lly work. Your best bet is to warn the user:
window.onbeforeunload = function() { return "Your work will be lost."; };
This page does list a number of ways you could try to disable the back button, but none are guaranteed:
http://www.irt.org/script/311.htm
...
How to use SCNetworkReachability in Swift
...his is how you would do it in Swift 2.0 (Xcode 7):
import SystemConfiguration
func connectedToNetwork() -> Bool {
var zeroAddress = sockaddr_in()
zeroAddress.sin_len = UInt8(sizeofValue(zeroAddress))
zeroAddress.sin_family = sa_family_t(AF_INET)
guard let defaultRouteReachabil...
What's the fuss about Haskell? [closed]
...aving worked on learning on Haskell for a month now, is the fact that functional programming twists your brain in interesting ways: it forces you to think about familiar problems in different ways: instead of loops, think in maps and folds and filters, etc. In general, if you have more than one pers...
Visual Studio Immediate window: how to see more than the first 100 items
...f an object with over 300 properties in the Immediate Window of Visual Studio 2005. Only the first 100 items are displayed, followed by this caption:
...
How to re-sync the Mysql DB if Master and slave have different database incase of Mysql replication?
...
This is the full step-by-step procedure to resync a master-slave replication from scratch:
At the master:
RESET MASTER;
FLUSH TABLES WITH READ LOCK;
SHOW MASTER STATUS;
And copy the values of the result of the last command somewhere.
Without closing the connection to the client (because it wo...