(import pq)
(def conn (pq/connect "postgresql://localhost?dbname=postgres"))
(pq/exec conn "create table users(name text, data jsonb);")
(pq/exec conn "insert into users(name, data) values($1, $2);" "ac" (pq/jsonb @{"some" "data"}))
(pq/row conn "select * from users where name = $1;" "ac")
{:name "ac" :data @{"some" "data"}}
(pq/all conn "select * from users")
[{:name "ac" :data @{"some" "data"}} ...]
(pq/val conn "select data from users where name = $1;" "ac")
@{"some" "data"}

(import pq)
...
(pq/tx conn {:mode "isolation serializable read only" :retry true}
  (unless (pq/val conn "select ....")
    (pq/rollback conn))
  (pq/val conn "select ...."))

(import pq)
...

# directly insert custom encoding.
(pq/exec conn "insert into tab(x) values($1);" [TYPEOID ISBINARY BYTES])

# use a method for custom type encoding.
(pq/exec conn "insert into tab(x) values($1);" {:pq/marshal (fn [self] [TYPEOID ISBINARY BYTES])})

# Add a custom type decoder.
(put pg/*decoders* TYPEOID custom-decoder)
(pq/all conn "select * from tab;")

(import pq)
...
(try
  ...
  ([err] (when (pq/error? err)
    (def msg (pq/result-error-field err ...)))))