Genealogy Query in Oracle

Question

I'm trying to fetch a genealogy tree of animals from my Oracle database.

Here's the table:

Animal
------------------------
Animal_ID
Parent_Male_ID
Parent_Female_ID
....
....
------------------------

If I specify an animal, I can get all of its descendants (on the male side) using something like this:

SELECT *
FROM animal
START WITH animal_id = 123
CONNECT BY PRIOR animal_id = parent_male_id

I'm trying to find a way to extend this in such a way that if I specify an animal, it will fetch both parents and then will fetch all of their descendants.

Any thoughts? (this is Oracle 9.2)

Answer 1

SELECT  *
FROM    animal
START WITH
        animal_id IN
        (
        SELECT  parent_male_id
        FROM    animal
        WHERE   animal_id = 123
        UNION ALL 
        SELECT  parent_female_id
        FROM    animal
        WHERE   animal_id = 123
        )
CONNECT BY
        PRIOR animal_id IN (parent_male_id, parent_female_id)

This query, however, will be quite slow.

Better to use this one:

SELECT  DISTINCT(animal_id) AS animal_id
FROM    (
        SELECT  0 AS gender, animal_id, father AS parent
        FROM    animal
        UNION ALL
        SELECT  1, animal_id, mother
        FROM    animal
        )
START WITH
        animal_id IN
        (
        SELECT  father
        FROM    animal
        WHERE   animal_id = 9500
        UNION ALL 
        SELECT  mother
        FROM    animal
        WHERE   animal_id = 9500
        )
CONNECT BY
        parent = PRIOR animal_id
ORDER BY
        animal_id

, which will use HASH JOIN and is much faster.

See this entry in my blog for performance details:

• Genealogy query on both parents

Answer 2

here is some further reading:

http://dev.mysql.com/tech-resources/articles/hierarchical-data.html