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 1. Mapping Microsoft SQL Server and Windows Azure SQL Database Data Types to Unicode Data Types
SQL Server Data Type Mapped to. . .
nchar1 SQL_WCHAR
ntext1 SQL_WLONGVARCHAR
nvarchar1 SQL_WVARCHAR
nvarchar(max)1,2 SQL_WLONGVARCHAR
sysname SQL_WVARCHAR
xml3 SQL_WLONGVARCHAR

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 Progress DataDirect for ODBC Drivers Reference for a more detailed explanation of Unicode.

1 Not supported for Microsoft Fabric.
2 nvarchar(max) and xml are supported for Microsoft SQL Server 2005 and higher.
3 nvarchar(max) and xml are supported for Microsoft SQL Server 2005 and higher.