Genealogy tree mysql

问题

I'm trying to create a structure to store and read dogs pedigree using php and mysql.

I found on stackoverflow this kind of structure, and it seems to be efficient: Inbreeding-immune database structure

TABLE people (id, name, father_id, mother_id );
TABLE relatives ( person_id, ancestor_id );

There is a working example here: http://sqlfiddle.com/#!2/0bd39/10

Is it possible to retrieve simply a ordered tree or a subtree (for example 4 or 5 generations) starting by an id?

EDIT

I'm trying to get the data from using the first table...but with 4-5 generations the resulting query is very very heavy. I fear that with a large amount of information in the DB, getting the genealogy could be to much slow and unusable.

SELECT 
    t1.name AS lev1, t2.name as f, ff1.name as ff1, fm1.name as fm1, t3.name as m, 
    mf1.name as mf1, mm1.name as mm1, .......
FROM people AS t1
LEFT JOIN people AS t2  ON t2.id = t1.father_id
 LEFT JOIN people AS ff1 ON ff1.id = t2.father_id
 LEFT JOIN people AS fm1 ON fm1.id = t2.mother_id
   ...
LEFT JOIN people AS t3  ON t3.id = t1.mother_id
 LEFT JOIN people AS mf1 ON mf1.id = t3.father_id
 LEFT JOIN people AS mm1 ON mm1.id = t3.mother_id
    ...
WHERE t1.id = 6;

回答1:

This sort of this is probably better suited for a graph style of data store. Something akin to how facebook keeps hierarchies of relationships.

If you are bound and determined to use MySQL you could probably get away with your schema by using a recursive search. Since your tree can be of variable depth you could start self-joining at given location and 'walk' down a branch recursing until you didn't find anymore descendants. Return that branch and start down the next one. Similar process for traversing up to find parents.

回答2:

I had this very issue with fish lineages. I found that dumping an adjacency list (like the one you've posted) to a dedicated tree builder like GraphViz was the best solution.

来源：https://stackoverflow.com/questions/14937909/genealogy-tree-mysql