Question

https://stackoverflow.com/questions/574805/how-to-einski-strings-in-msql-using-php>。问题我试图使我的方案更加安全,将扼杀物改成黑体,比较这些价值,而不是直接和危险地利用用户的扼杀。我修改了有关这个问题的法典,以添加一项转换:

function mssql_escape($data) {
    if(is_numeric($data))
        return $data;

    $data = iconv("ISO-8859-1", "UTF-16", $data);

    $unpacked = unpack( H*hex , $data);

    return  0x  . $unpacked[ hex ];
}

我之所以这样做,是因为在我的数据库中,我使用的是Nvarchar,而不是varchar。现在,当我通过时,就在营地一侧。

0xfeff00680065006c006c006f00200077006f0072006c00640021

随后,我提出以下问题:

 declare @test nvarchar(100);
 set @test =  hello world! ;
 select CONVERT(VARBINARY(MAX), @test);

结果是:

0x680065006C006C006F00200077006F0072006C0064002100

现在,你注意到这些数字是同比的。除了零号拖车外,唯一的差别是疲软。为什么会出现这种情况? 我认识到,我必须做的是转变,但我真的要知道我们在那里,而不是只是作一个假设。谁能向我解释,为什么营地决定在我的牛肉前 throw下 f。

Answer 1

安德鲁,我似乎回答了你的许多问题。该链接解释:

So the people were forced to come up with the bizarre convention of storing a FE FF at the beginning of every Unicode string; this is called a Unicode Byte Order Mark and if you are swapping your high and low bytes it will look like a FF FE and the person reading your string will know that they have to swap every other byte. Phew. Not every Unicode string in the wild has a byte order mark at the beginning.

Wikipedia解释说:

If the 16-bit units are represented in big-endian byte order, this BOM character will appear in the sequence of bytes as 0xFE followed by 0xFF. This sequence appears as the ISO-8859-1 characters þÿ in a text display that expects the text to be ISO-8859-1.

if the 16-bit units use little-endian order, the sequence of bytes will have 0xFF followed by 0xFE. This sequence appears as the ISO-8859-1 characters ÿþ in a text display that expects the text to be ISO-8859-1.

因此,你用FEFF展示的代码,这意味着该代码在大端终端电离层。 “UTF-16LE”很少为终点人员使用,而Kall将理解这一点。只要你只用两条tes子重新计算,就只能同时工作。

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