Pass unicode data in SQL Server 2008 stored procedure parameter

Question

Hi,
I want to pass unicode data in a SQL stored procedure. But I am not sure that how to append N with NVarchar datatype.
For example I Create a table LocalizationTest and wants to insert a few records.
Create table LocalizationTest
    Field1 NVarchar(255)
INSERT INTO LocalizationTest
VALUES(N'123 Illini Dr, 東皮奧里亞, 8989')
the above given statement works.
To explain it more , script A works but script B does not work.
DECLARE @X NVARCHAR(255)
[A]
SET @X=N '123 Illini Dr, 東皮奧里亞, 8989'
INSERT INTO LocalizationTest
VALUES(@X)
[B]
SET @X= '123 Illini Dr, 東皮奧里亞, 8989'
INSERT INTO LocalizationTest
VALUES(@X)
What is the correct way to execute script B because @X will be passed in a SQL Stored Procedure?
Thanks
Sharma M.

Answer 1

If you do not pass the value as a Unicode value there is nothing left of the Unicode characters but question marks. Once this has happened, AFAIK there is no way to undo it (other than resetting the value as Unicode characters again).
Affirmative.
Demo - This is what happens if you convert UNICODE (nvarchar) to varchar with implicit conversion (try to force 2 bytes into one byte).
3F hex is '?'.
CREATE TABLE #LocalizationTest (Field1 VARCHAR(255))
INSERT INTO #LocalizationTest
VALUES(N'123 Illini Dr, 東皮奧里亞, 8989')
DECLARE @X NVARCHAR(255), @dSQL NVARCHAR(MAX)
SET @X=N'123 Illini Dr, 東皮奧里亞, 8989'
INSERT INTO #LocalizationTest VALUES(CONVERT(NVARCHAR(255),@X))
SET @dSQL = N'INSERT INTO #LocalizationTest VALUES(N'''+@X+''')'
PRINT @dSQL
EXEC sp_ExecuteSQL @dSQL
SELECT *, Field1Bin=convert(binary(30), Field1) FROM #LocalizationTest
DROP TABLE #LocalizationTest
123 Illini Dr, ?????, 8989 0x31323320496C6C696E692044722C203F3F3F3F3F2C203839383900000000
123 Illini Dr, ?????, 8989 0x31323320496C6C696E692044722C203F3F3F3F3F2C203839383900000000
123 Illini Dr, ?????, 8989 0x31323320496C6C696E692044722C203F3F3F3F3F2C203839383900000000
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