MDAC 2.5 SDK - ODBC Desktop Database Drivers
When the Microsoft Access, Microsoft Excel, or Paradox driver is used, and the length of a text or binary column is not specified (or is specified as 0), the column length will be set to 255.
When the dBASE driver is used, and the length of a text or binary column is not specified (or is specified as 0), the column length will be set to 254.
A maximum of 255 columns is supported.
When the Microsoft Excel driver is used on a Microsoft Excel 5.0, 7.0, or 97 data source, a worksheet cannot be created with the same name as a worksheet that was previously dropped. When the Microsoft Excel driver is used to access a version 5.0, 7.0, or 97 worksheet, a DROP TABLE statement clears the worksheet, but does not delete the worksheet name.
When the Paradox driver is used, columns cannot be added once an index has been defined on a table. If the first column of the argument list of a CREATE TABLE statement creates an index, a second column cannot be included in the argument list.