Issue of Updating Serial Number in Database Table

[erncd1]

My entries are saved in a table having a field of Serial No alongwith other fields to keep them in sorted order. However when we reorder the record in MSFlexgrid/Listbox, what is the economical procedure adopted by professional to update that record order in the table.

The example is given below:

Sr. No., Saved Order, Changed Order

1, A, A
2, B, C
3, C, B
4, D, D
5, E, E

The letter C was placed previously at Sr. No.3. After shifting, it goes to Sr. No.2. My procedure is to store the previous index of letter “C” in a variable, open the table order by Sr. No. Move the record to InxdexVariable and change the value of field Sr. No. = IndexVariable -1 in case of shifting Up or Index Variable + 1 in case of Shifting Down. In a similar way I amend the second affecting record “B”.

I would like also to know the procedure in case of removing a record and then updating the rest of Sr. Nos. in a table.