Jason Young (Morgon)
morgon at mygamercard.net
Tue Jul 22 17:44:02 EDT 2008
In my short experience (and through confirmation with SQL Server MVPs at
Microsoft), inserting UTF8 strings into nvarchar fields require N''
I know that FreeTDS doesn't care about the N prefix, but when doing my
tests, I was only able to fully extract inserted 'UTF8' data when
inserting using the N prefix into an nvarchar field.
I'm most certainly open to examples (re-creatable code/environment)
where this is not needed, I was just reflecting what worked in my
Here's what I have --
CREATE TABLE dbo.utf8test (
textfield nvarchar(50) NOT NULL
$MSDB = mssql_connect($DBHost, $DBLogin $DBPassword) or die ("Could not
connect to server\n");
mssql_query("INSERT INTO utf8test (textfield) VALUES ('<UTF8 Text>')");
//Japanese in this particular case.
$Result = mssql_query("SELECT * FROM utf8test");
This always returns question marks, both CLI/CGI (browser) and in the
When I place the N in front of the quoted UTF8 text, it is stored and
Do you have different results, James?
Thanks for your help
James K. Lowden wrote:
> Jason Young (Morgon) wrote:
>> SQL Server is a pain in regards to sending UTF strings, as you'll need
>> to prefix all of your quoted strings with capital N, for example:
>> INSERT INTO utf8_table (utf8string) VALUES (N'???')
> I don't see what difference the 'N' prefix makes.
> "Unicode strings have a format similar to character strings but are
> preceded by an N identifier (N stands for National Language in the SQL-92
> standard). The N prefix must be uppercase. For example, 'Michél' is a
> character constant while N'Michél' is a Unicode constant. Unicode
> constants are interpreted as Unicode data, and are not evaluated by using
> a code page."
> Remember that Win32 clients use USC-2. The SQL text is sent to the server
> as USC-2. That is, the server sees 18 bytes:
> $ iconv -f iso8859-1 -t ucs-2 | hexdump -C
> 00000000 4e 00 27 00 4d 00 69 00 63 00 68 00 e9 00 6c 00
> 00000010 27 00
> No UTF-8 anywhere in sight.
> I don't know how to interepret Microsoft's statement though. *All* SQL
> text is transmitted as UCS-2. When that 'e9 00' arrives, the server knows
> it's UCS-2, regardless of whether the string is preceded by a 'N' or not.
> Once the constants are parsed out, each one has to be converted to the
> column's encoding, based on its "collation" (unless it's a UCS-2 column,
> of course). So I don't see any "interpretation" happening based on the
> 'N' prefix.
> FreeTDS of course has to convert from the client's encoding to UCS-2. It
> will do so regardless of the data; the 'N' prefix means nothing to
> FreeTDS. The result is precisely as above: the data arrive as UCS-2, and
> I see no effect of using the 'N' prefix or not.
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