I would guess its dependent on the ODBC driver you are using. If it does not support (or request) 2008 or later TDS version, then the type DATE will correctly be returned as VARCHAR.

You could run a query to get the table column info:

SELECT tbl.name AS tblName,
    col.name AS fldName,
    typ.name AS Type,
    col.length AS length,
    col.isnullable AS isnullable,
    cmt.text AS DefaultVal
FROM sys.sysobjects tbl
INNER JOIN sys.syscolumns col
    ON col.id = tbl.id
INNER JOIN sys.systypes typ
    ON typ.xtype = col.xtype
LEFT JOIN sys.sysobjects cnst
    ON cnst.xtype = 'D'
    AND cnst.parent_obj = tbl.id
    AND col.cdefault = cnst.id
LEFT JOIN sys.syscomments cmt
    ON cmt.id = cnst.id
WHERE  (tbl.xtype = 'U' OR tbl.xtype = 'V')
    AND (tbl.name <> N'dtproperties') 
    AND (tbl.name <> N'sysconstraints') 
    AND (tbl.name <> N'syssegments') 
    AND (tbl.name = 'MyTestTable')
ORDER BY tbl.name, col.name

Output:

tblName     fldName     Type    length  isnullable  DefaultVal
MyTestTable action      varchar 10  0   NULL
MyTestTable actionby    varchar 100 0   NULL
MyTestTable actiondate  datetime    8   0   NULL
MyTestTable colname     varchar 50  0   NULL
MyTestTable formfieldname   varchar 100 0   NULL
MyTestTable newvalue    varchar -1  0   NULL
MyTestTable oldvalue    varchar -1  0   NULL
MyTestTable primarykey  varchar 100 0   NULL
MyTestTable sequence    int 4   0   NULL

When the type comes back as WVARCHAR(-9) , you have to look at the sqlTypeName as obtained by

SQLCHAR     *sqlTypeName        = NULL;
SQLINTEGER  sqlTypeNameLength   = 0;

sqlTypeName = (unsigned char *)(strSchemaName.GetBuffer(MAX_TEXT_FILE_LINE_LENGTH));

SQLBindCol(m_hSQL,6,SQL_C_CHAR,sqlTypeName,MAX_TEXT_FILE_LINE_LENGTH, &sqlTypeNameLength);

It will contain date , time , or datetime2 . Type WVARCHAR(-9) is not returned when the data column is a datetime .