Automatic type conversion

Native Clojure maps, vectors and sequences are accepted as parameters; the target SQL type reported by PostgreSQL decides the conversion.

(jdbc/execute! db ["SELECT ?::int[]  AS arr" [1 2 3 4]])
;; => [{:arr [1 2 3 4]}]
(jdbc/execute! db ["SELECT ?::json   AS obj" {"foo" "bar"}])
;; => [{:obj {"foo" "bar"}}]
(jdbc/execute! db ["SELECT ?::timestamptz AS epoch" 1])
;; => [{:epoch #inst "1970-01-01T00:00:00.001-00:00"}]

• Maps — json/jsonb columns accept any map; geometry columns accept GeoJSON-like maps. Extend with (defmethod psql.types/map->parameter :mytype [m _] ...).
• Vectors — array columns (int[], text[], ...) accept vectors; inet accepts [192 168 1 11]. Extend with (defmethod psql.types/vec->parameter :mytype [v _] ...).
• Other seqables (lists, lazy seqs) are treated like vectors.
• Numbers bound to timestamp/timestamptz become java.sql.Timestamp. Extend with (defmethod psql.types/num->parameter :mytype [n _] ...).
• Keywords bind to enum columns by name: :happy goes into a mood enum as 'happy' (and ?::mood casts work). Enum values read back as plain strings.

On the way out, json/jsonb parse to Clojure data and arrays become vectors.

PostgreSQL geometric types

psql.core constructs the built-in org.postgresql.geometric.* types:

(pg/point 1 2)              ;=> (1.0,2.0)
(pg/box [1 2] [3 4])        ;=> (1.0,2.0),(3.0,4.0)
(pg/circle [25 30] 5)       ;=> <(25.0,30.0),5.0>
(pg/line (pg/point 1 2) (pg/point 3 4))
(pg/lseg [1 2] [10 20])
(pg/path [[1 2] [10 20] [50 100]] true)
(pg/polygon [[1 2] [3 4] [5 6]])