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Does MySQL ignore null values on unique constraints?
... '1' for key 'x'
INSERT table1 VALUES (NULL);
INSERT table1 VALUES (NULL);
SELECT * FROM table1;
Result:
x
NULL
NULL
1
This is not true for all databases. SQL Server 2005 and older, for example, only allows a single NULL value in a column that has a unique constraint.
...
Is “IF” expensive?
...nation on Cell Performance. Another fun one is this post about branchless selections on the Real Time Collision Detection Blog.
In addition to the excellent answers already posted in response to this question, I'd like to put in a reminder that although "if" statements are considered expensive low...
How to recursively delete an entire directory with PowerShell 2.0?
... it useful to see what I'm about to delete by running
Get-Tree some_dir | select fullname
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What are the differences between Deferred, Promise and Future in JavaScript?
...
These answers, including the selected answer, are good for introducing promises
conceptually, but lacking in specifics of what exactly the differences are in
the terminology that arises when using libraries implementing them (and there
are important diff...
获取文件系统映像及恢复删除的数据（FAT文件系统格式描述） - C/C++ - 清泛...
...str()<< L"/n";
}
int driveIndex;
std::cin >> driveIndex;//selecting a disk
std::vector<unsigned char> buffer;
//creating a path
std::wstring dumpPath(L"////.//PhysicalDrive");
wchar_t index[MAX_PATH];
_itow(devices.at(driveIndex).vHarddiskIndexes[0], index , MAX_P...
获取文件系统映像及恢复删除的数据（FAT文件系统格式描述） - C/C++ - 清泛...
...str()<< L"/n";
}
int driveIndex;
std::cin >> driveIndex;//selecting a disk
std::vector<unsigned char> buffer;
//creating a path
std::wstring dumpPath(L"////.//PhysicalDrive");
wchar_t index[MAX_PATH];
_itow(devices.at(driveIndex).vHarddiskIndexes[0], index , MAX_P...
获取文件系统映像及恢复删除的数据（FAT文件系统格式描述） - C/C++ - 清泛...
...str()<< L"/n";
}
int driveIndex;
std::cin >> driveIndex;//selecting a disk
std::vector<unsigned char> buffer;
//creating a path
std::wstring dumpPath(L"////.//PhysicalDrive");
wchar_t index[MAX_PATH];
_itow(devices.at(driveIndex).vHarddiskIndexes[0], index , MAX_P...
获取文件系统映像及恢复删除的数据（FAT文件系统格式描述） - C/C++ - 清泛...
...str()<< L"/n";
}
int driveIndex;
std::cin >> driveIndex;//selecting a disk
std::vector<unsigned char> buffer;
//creating a path
std::wstring dumpPath(L"////.//PhysicalDrive");
wchar_t index[MAX_PATH];
_itow(devices.at(driveIndex).vHarddiskIndexes[0], index , MAX_P...
获取文件系统映像及恢复删除的数据（FAT文件系统格式描述） - C/C++ - 清泛...
...str()<< L"/n";
}
int driveIndex;
std::cin >> driveIndex;//selecting a disk
std::vector<unsigned char> buffer;
//creating a path
std::wstring dumpPath(L"////.//PhysicalDrive");
wchar_t index[MAX_PATH];
_itow(devices.at(driveIndex).vHarddiskIndexes[0], index , MAX_P...
获取文件系统映像及恢复删除的数据（FAT文件系统格式描述） - C/C++ - 清泛...
...str()<< L"/n";
}
int driveIndex;
std::cin >> driveIndex;//selecting a disk
std::vector<unsigned char> buffer;
//creating a path
std::wstring dumpPath(L"////.//PhysicalDrive");
wchar_t index[MAX_PATH];
_itow(devices.at(driveIndex).vHarddiskIndexes[0], index , MAX_P...