Table custom re-ordering

When I re-order rows in my table it re-assigns numbers starting from one, like for example if I have a table with records ordered by the number column and numbers are between 4 and 9 and when I drag the row with number 8 to first position it re-assigns the numbering of entire table from 1 to 6 overriding the previous values of other columns as well. Check the following images for example. I have a Novel model which has many Series and each series has many Chapters the Chapters are associated with distinct numbers linked with grand parent Novel adjacent chapters can be in two separate Series like Chapter 4 can be in Series 1 and Chapter 5 can be in Series 2