取回索引信息的PostgreSQL 8.4

Question

我需要獲取對特定表有關指數的以下信息：

• 索引名被索引
• 獨特或不
• 列？

如何在PostgreSQL 8.4中做到這一點？

注意：我必須能夠用PHP調用這個東西。只是說...

編輯：我第一次有這樣的查詢，但它僅適用起始PostgreSQL的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

你可以簡單地使用pg_indexes，其中將包括完整的CREATE TABLE語句（和因此有關列和唯一性的信息）。

或者，下面應該工作：

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 

它不以正確的順序返回列雖然。但我沒有時間深入研究。