What I'd do in this case is create 10 temp cursors each with the appropriate structures including the flag, APPEND TYPE SDF into each cursor from the files and then scan the cursors adding, updating or deleting from the real tables.

>They are about 10 tables in a database, which data all come from SDF format files. Besides necessary data, at the head of every line, there is a flag character,
>
>A, for add, which mean whole line data, of couse except flag character, will be added into correponded table;
>U, for update, replace existing record;
>D, for delete, erase existing record;
>
>In every SDF format file, there are possibility to hold above 3 lines in the same time, and the lines are about handreds or thousands, that is my question come from.