Fetch index information in PostgreSQL 8.4 - php

Question

I need to fetch the following information about indices on a specific table:
index name
columns that are indexed
unique or not?
How can I do that in PostgreSQL 8.4?
NOTE: I have to be able to call this stuff with PHP. Just saying...
EDIT: I first had this query, but it only works starting with PostgreSQL 9.0:
SELECT t.relname AS table_name,
relname AS index_name,
a.attname AS column_name,
ix.indisunique
FROM pg_class t,
pg_class i,
pg_index ix,
pg_attribute a,
pg_constraint c
WHERE t.oid = ix.indrelid
AND i.oid = ix.indexrelid
AND a.attrelid = t.oid
AND i.oid = c.conindid
AND a.attnum = ANY(ix.indkey)
AND c.contype != 'p'
AND t.relkind = 'r'
AND t.relname = 'tablename'
ORDER BY t.relname, i.relname

Answer 1

You could simply use pg_indexes which will include the full CREATE TABLE statement (and therefor the information about the columns and the uniqueness).
Alternatively, the following should work:
select t.relname as table_name,
ix.relname as index_name,
array_to_string(array_agg(col.attname), ',') as index_columns,
i.indisunique
from pg_index i
join pg_class ix on ix.oid = i.indexrelid
join pg_class t on t.oid = i.indrelid
join (select ic.indexrelid,
unnest(ic.indkey) as colnum
from pg_index ic) icols on icols.indexrelid = i.indexrelid
join pg_attribute col on col.attrelid = t.oid and col.attnum = icols.colnum
where t.relname = 'tablename'
group by t.relname, ix.relname, i.indisunique
order by t.relname,
ix.relname
It doesn't return the columns in the correct order though. But I didn't have time to dig deeper into that.