Question

What’s the best way to store a linked list in a MySQL database so that inserts are simple (i.e. you don’t have to re-index a bunch of stuff every time) and such that the list can easily be pulled out in order?

Answer 1

Store an integer column in your table called ‘position’. Record a 0 for the first item in your list, a 1 for the second item, etc. Index that column in your database, and when you want to pull your values out, sort by that column.

 alter table linked_list add column position integer not null default 0;  alter table linked_list add index position_index (position);  select * from linked_list order by position; 

To insert a value at index 3, modify the positions of rows 3 and above, and then insert:

 update linked_list set position = position + 1 where position >= 3;  insert into linked_list (my_value, position) values ('new value', 3);