大约有 41,000 项符合查询结果（耗时：0.0606秒） [XML]
When to use a View instead of a Table?
...ose facts from a certain client.
Views for insertion/updates:
You can handle security issues with views by using such functionality as Oracle's "WITH CHECK OPTION" clause directly in the view
Drawbacks
You lose information about relations (primary keys, foreign keys)
It's not obvious whether...
Different ways of adding to Dictionary
What is the difference in Dictionary.add(key, value) and Dictionary[key] = value ?
8 Answers
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What does set -e mean in a bash script?
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From help set :
-e Exit immediately if a command exits with a non-zero status.
But it's considered bad practice by some (bash FAQ and irc freenode #bash FAQ authors). It's recommended to use:
trap 'do_something' ERR
to run do_something function when errors occur.
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Effect of a Bitwise Operator on a Boolean in Java
The bitwise operators are supposed to travel variables and operate on them bit by bit. In the case of integers, longs, chars this makes sense. These variables can contain the full range of values enforced by their size.
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What browsers support HTML5 WebSocket API?
...fill.
See caniuse for the current status of WebSockets support in desktop and mobile browsers.
See the test reports from the WS testsuite included in Autobahn WebSockets for feature/protocol conformance tests.
Server side
It depends on which language you use.
In Java/Java EE:
Jetty 7.0 supp...
Is there a good charting library for iPhone? [closed]
I have a need to render and display charts (bar charts for now, but more types may be needed later) in an iPhone app I'm working on. I've done some looking around and it doesn't look like there are any really good, mature charting libraries for iPhone yet. I've also looked for something written for ...
C: differences between char pointer and array [duplicate]
...ent scope's stack space, it is unspecified exactly where it will be stored and should not be modified.
Edit: As pointed out by Mark, GMan, and Pavel, there is also a difference when the address-of operator is used on either of these variables. For instance, &pmessage returns a pointer of type ...
Most efficient method to groupby on an array of objects
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Here is one that outputs array and not object: groupByArray(xs, key) { return xs.reduce(function (rv, x) { let v = key instanceof Function ? key(x) : x[key]; let el = rv.find((r) => r && r.key === v); ...
Best way to define private methods for a class in Objective-C
I just started programming Objective-C and, having a background in Java, wonder how people writing Objective-C programs deal with private methods.
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The difference between the 'Local System' account and the 'Network Service' account?
...the COM object. The error returned from the COM object creation is not a standard COM error (I think it's specific to the COM object being created).
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