Data structure can contain millions of objects. For searching and filtering them you can use Directual Query Language (DQL).
Here are some examples of DQL-requests:
42 is a synonym to
id = "42" — it finds the object with ID = 42.
(title like "sun" AND year < 1950) OR is_good = "true"— finds objects of two groups. First: with titles similar to The Sun also rises or Under the Blood-Red Sun, and with year less then 1950. Plus second: with is_good equals true.
birth_date <= "2000-04-09T00:00:00"— finds objects with birth_date before 9th April 2000.