Query API

The query API is used for generating Datomic queries, whether to send via an external client or via the persistence API. The two methods used to generate a query are .where and .filter, both of which are chainable.

To get query data and args for a query, call .data on a Query.

If you are using a persistence API, you can ask Query to get the results of a Datomic query. Diametric::Query is an Enumerable. To get the results of a query, use Enumerable methods such as .each or .first. Query also provides a .all method to run the query and get the results.

query = Datomic::Query.new(Person).where(:name => "Clinton Dreisbach")
query.data
# Datomic query:
# [:find ?e ?name ?email ?birthday ?iq ?website
#  :from $ ?name
#  :where [?e :person/name ?name]
#         [?e :person/email ?email]
#         [?e :person/birthday ?birthday]
#         [?e :person/iq ?iq]
#         [?e :person/website ?website]]
# Args:
#   ["Clinton Dreisbach"]
#
# Returns as an array, [query, args].

query = Datomic::Query.new(Person).where(:name => "Clinton Dreisbach").filter(:>, :iq, 150)
query.data
# Datomic query:
# [:find ?e ?name ?email ?birthday ?iq ?website
#  :from $ ?name
#  :where [?e :person/name ?name]
#         [?e :person/email ?email]
#         [?e :person/birthday ?birthday]
#         [?e :person/iq ?iq]
#         [?e :person/website ?website]
#         [> ?iq 150]
# Args:
#   ["Clinton Dreisbach"]
#
# Returns as an array, [query, args].