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Best way to do multi-row insert in Oracle?
...AG_NAME,PAG_ACTIVE)
select 8000,0,'Multi 8000',1 from dual
union all select 8001,0,'Multi 8001',1 from dual
The thing to remember here is to use the from dual statement.
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Boost.Asio的简单使用(Timer,Thread,Io_service类) - C/C++ - 清泛网 - 专注C/C++及内核技术
... asio::write(socket, asio::buffer(message),
asio::transfer_all(), asio::ignore_error());
}
}
最后处理异常
catch (std::exception& e)
{
std::cerr << e.what() << std::endl;
}
return 0;
运行示例:运行服务器,然后运行上一节的客户端,在win...
What's the difference between SortedList and SortedDictionary?
...<TKey,TValue> ? Are there any circumstances where you would specifically use one and not the other?
7 Answers
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When is “i += x” different from “i = i + x” in Python?
...
This depends entirely on the object i.
+= calls the __iadd__ method (if it exists -- falling back on __add__ if it doesn't exist) whereas + calls the __add__ method1 or the __radd__ method in a few cases2.
From an API perspective, __iadd__ is supposed to be used fo...
Meaning of @classmethod and @staticmethod for beginner? [duplicate]
...ect as the first parameter, whereas staticmethod can have no parameters at all.
Example
class Date(object):
def __init__(self, day=0, month=0, year=0):
self.day = day
self.month = month
self.year = year
@classmethod
def from_string(cls, date_as_string):
...
Use cases for the 'setdefault' dict method
...e case: Grouping items (in unsorted data, else use itertools.groupby)
# really verbose
new = {}
for (key, value) in data:
if key in new:
new[key].append( value )
else:
new[key] = [value]
# easy with setdefault
new = {}
for (key, value) in data:
group = new.setdefault(k...
How to avoid “if” chains?
...ep<X>() should evaluate only if the previous one succeeded (this is called short circuit evaluation)
executeThisFunctionInAnyCase() will be executed in any case
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Underscore prefix for property and method names in JavaScript
...
Welcome to 2019!
It appears a proposal to extend class syntax to allow for # prefixed variable to be private was accepted. Chrome 74 ships with this support.
_ prefixed variable names are considered private by convention but are still public.
This syntax tries to be both terse and int...
How to calculate the difference between two dates using PHP?
...ferred way of doing this is like described by jurka below. My code is generally only recommended if you don't have PHP 5.3 or better.
Several people in the comments have pointed out that the code above is only an approximation. I still believe that for most purposes that's fine, since the usage of...
How do you build a Singleton in Dart?
... There's the weird syntax Singleton._internal(); that looks like a method call when it's really a constructor definition. There's the _internal name. And there's the nifty language design point that Dart lets you start out (dart out?) using an ordinary constructor and then, if needed, change it to a...