How to modify the structure of a Paradox table at runtime (Views: 29)
Problem/Question/Abstract: I am upgrading an application and need to add fields to a Paradox TTable database. The application should inspect the existing database file structure and upgrade the customers existing database if necessary. Answer: First, open the files using a TTables exclusively, and check for fields. I was adding fields so I used the following code: with tblEmployer do begin open; lFoundAddCalcMethod := FindField('RetireCalcMethod') <> nil; lFoundRetireFundMethod := FindField('RetireFundMethod') <> nil; close; end; If I was altering a field (for example, say I wanted to make a field change from Integer to String), you could assing the result of FindField to a TField variable and check it. Then I alter the table as needed: if not lFoundAddCalcMethod then QryAddRetireCalcMethod.ExecSQL; and the SQL part of the TQuery: alter table "MAXXEMPL.DB" add RetireCalcMethod character(2), add RetireFundDollar Float, add RetireFundPercent Float, add LocalTaxMthd character(2); |