What to call a column that references another row in the same table?

I have inherited a table that contains a column that is used to "chain" between various related rows within the same table.

For instance:
id, bar, reference_id

• 1, 'foo', 2

• 2, 'foo', 3

• 3, 'foo'

I have no idea what to call this structure in order to search for how I should deal with it. The idea is that the table maintains a sort of living history within itself. (my problem is that I may have row 1 or 2, but I need to get to row 3 somehow that is agnostic to the number of 'levels' that I need to traverse)

There are several things in play here. A table that has a self-referential key is said to have a reflexive foreign key, though that doesn't look like it applies here because you'll have missing values.

What you're looking for is a hierarchical query, which can be achieved in Oracle by using a CONNECT BY clause.

They can be a bit difficult to get your head around at first, but there are plenty of good examples on the internet. A good one to start with is here. For once, the official documentation is quite clear too!

Something like:

SELECT id, bar, reference_id, LEVEL
FROM yourtable
CONNECT BY PRIOR reference_id = id;

... will get you started on your data.

StackExchange Database Administrators Q#31773, answer score: 7