Unicode Support

The SQL Server Wire Protocol driver maps the Microsoft SQL Server and Windows Azure SQL Database data types to Unicode data types as shown in the following table:

Table 2. Mapping Microsoft SQL Server and Windows Azure SQL Database Data Types to Unicode Data Types
SQL Server Data Type	Mapped to. . .
datetimeoffset¹, ²	SQL_WVARCHAR
nchar	SQL_WCHAR
ntext	SQL_WLONGVARCHAR
nvarchar	SQL_WVARCHAR
nvarchar(max)³	SQL_WLONGVARCHAR
sysname	SQL_WVARCHAR
xml⁴	SQL_WLONGVARCHAR

¹ Supported only for Microsoft SQL Server 2008 and higher, and Windows Azure SQL Database.

² Datetimeoffset mapping changes based on the setting of the Fetch TSWTZ as Timestamp option.

³ nvarchar(max) and xml are supported for Microsoft SQL Server 2005 and higher.

⁴ nvarchar(max) and xml are supported for Microsoft SQL Server 2005 and higher.

The driver supports the Unicode ODBC W (Wide) function calls, such as SQLConnectW. This allows the Driver Manager to transmit these calls directly to the driver. Otherwise, the Driver Manager would incur the additional overhead of converting the W calls to ANSI function calls, and vice versa.

See "UTF-16 Applications on UNIX and Linux" for related details. Also, refer to "Internationalization, Localization, and Unicode" in the DataDirect Connect Series for ODBC Reference for a more detailed explanation of Unicode.