While reading about NoSQL,
MongoDB let's you store and search JSON objects.In that case, you don't
need to have the same "columns" in each "row"
The following ensued. Isn't it cute ?
CREATE TABLE mongo ( id SERIAL PRIMARY KEY, obj hstore NOT NULL );
INSERT INTO mongo (obj) SELECT ('a=>'||n||',key'||(n%10)||'=>'||n)::hstore
FROM generate_series(1,100000) n;
SELECT * FROM mongo LIMIT 10;
id | obj
----+-------------------------
1 | "a"=>"1", "key1"=>"1"
2 | "a"=>"2", "key2"=>"2"
3 | "a"=>"3", "key3"=>"3"
4 | "a"=>"4", "key4"=>"4"
5 | "a"=>"5", "key5"=>"5"
6 | "a"=>"6", "key6"=>"6"
7 | "a"=>"7", "key7"=>"7"
8 | "a"=>"8", "key8"=>"8"
9 | "a"=>"9", "key9"=>"9"
10 | "a"=>"10", "key0"=>"10"
CREATE INDEX mongo_a ON mongo((obj->'a')) WHERE (obj->'a') IS NOT NULL;
CREATE INDEX mongo_k1 ON mongo((obj->'key1')) WHERE (obj->'key1') IS NOT
NULL;
CREATE INDEX mongo_k2 ON mongo((obj->'key2')) WHERE (obj->'key2') IS NOT
NULL;
VACUUM ANALYZE mongo;
SELECT * FROM mongo WHERE (obj->'key1')='271';
id | obj
-----+---------------------------
271 | "a"=>"271", "key1"=>"271"
(1 ligne)
EXPLAIN ANALYZE SELECT * FROM mongo WHERE (obj->'key1')='271';
QUERY PLAN
---------------------------------------------------------------------------------------------------------------------
Index Scan using mongo_k1 on mongo (cost=0.00..567.05 rows=513 width=36)
(actual time=0.024..0.025 rows=1 loops=1)
Index Cond: ((obj -> 'key1'::text) = '271'::text)
Total runtime: 0.048 ms
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