You may have already found your answer, but I'm almost certain that the last two values are boolean values which represent, respectively, "Is this column a primary key?" and "Can this column accept NULL values?"
~CubicSpline
"No one tosses a Dwarf!
Comment on Re: finding field infomation with DBI and ODBC
DecimalDigits. The number of decimal digits of the column on the data source. If the number of decimal digits cannot be determined or is not applicable, the driver returns 0.
Nullable. Indicates whether the column allows null values.
Primary key information would be at least as useful to me as decimal digits. I'm guessing that decimal digits are the second argument to the number(,) datatype? In fact because of this, It doesn't seem like I'm going to be able to fully automate this process.
After over an hour of looking through ODBC and Access Documentation I still can't figure out exactly what datatypes map to which integers in the second column. It's maddening. I'm still working on a solution to this.