The following limits exist for the ODBC protocol:
Database Connectors allows an unlimited number of columns, but the database may have a limit, and the driver may have a smaller limit than the database. If you have too many columns, you will receive a database error on the table create (for example, open output).
To achieve the same sort or retrieval sequence under ODBC as under the Vision file system, place a BINARY directive immediately before each key field that contains signed numeric data. High values and low values can cause problems in key fields. If you want data that uses the BINARY directive to be stored as hexadecimal encoded CHAR types, you can specify A_ODBC_USE_CHAR_FOR_BINARY in the configuration file. Please note that this could potentially increase the size of your key beyond the driver maximum.