I have some complex engine control software that has to run under MS-DOS 6.2, but it needs to transfer data to SQL Server 7. What's the best way to connect to SQL Server from DOS?
You can use OSQL or ISQL to connect to SQL Server from the command line. Both of these utilities are Win32 command-line utilities that allow you to log in to a server and issue any SQL command. The OSQL utility supports the most functionality and uses ODBC to connect to SQL Server. The syntax "osql/?" provides a listing of all OSQL flags.
This syntax connects to a server and issues a query:
osql -S "servername" -U "sa" -d "pubs" -q "SELECT * FROM Authors"
To insert data into a database, you could put OSQL commands in a batch file or provide an input file of SQL INSERT commands. See the SQL Server BOL for details and syntax of OSQL.
If you have a straight DOS box, you need to install the 16-bit client that comes with SQL Server 6.5. Both the client and the 6.5 version of ISQL use DB-Lib, which doesn't support some SQL Server 7 features like unicode columns, varchar columns larger than 255, etc.