How can you generate a counter for ordered sets?
От | Christopher Maier |
---|---|
Тема | How can you generate a counter for ordered sets? |
Дата | |
Msg-id | 4E9181C4-E46A-4D0F-8A35-1EE1C64AC48E@email.unc.edu обсуждение исходный текст |
Ответы |
Re: How can you generate a counter for ordered sets?
|
Список | pgsql-sql |
I am in the process of transitioning a bioinformatics database from one schema to another, and I have to do some "massaging" of the data in order to do it. I have two tables, "gene" and "exon". Exon has a many-to-one relationship with Gene. The structure of the Gene table isn't important, but the Exon table looks like this: CREATE TABLE exon(id SERIAL PRIMARY KEY,gene INTEGER REFERENCES gene(id),start INTEGER,stop INTEGER ); Conceptually, all the exons for a given gene form a set, ordered by their "start" attribute. I need to add a new integer column to the table to store a counter for each exon that indicates their position in this ordering. Is there a straightforward way to populate this new position column? I've done an iterative solution in PL/pgSQL which works (slowly), but I was wondering if there was a more efficient way to do this kind of thing. Thanks in advance, Christopher Maier
В списке pgsql-sql по дате отправления: