Emacs PQ

PostgreSQL interface for Emacs.

usage

Simple usage with temporary connection.

(require 'pq)

;; these are default options.
(pq:with-temp-conn (list :host "127.0.0.1"
                         :port 5432
                         :user user-login-name
                         :database user-login-name
                         :password nil
                         :proc-name "pq")
  (pq:exec "CREATE TEMP TABLE person (id SERIAL PRIMARY KEY, name TEXT)")
  (pq:exec '("INSERT INTO person (name) VALUES ($1), ($2)" "someone" "anyone"))
  (pq:query "SELECT id, name FROM person ORDER BY id" (row columns row-idx)
    (message "row number: %d" row-idx)
    (seq-map-indexed
     (lambda (col idx)
       (message "    %s: %s" (aref col 0) (aref row idx)))
     columns)))

;; output:
;; row number: 0
;;     id: 1
;;     name: someone
;; row number: 1
;;     id: 2
;;     name: anyone

With persistent connection.

(defvar pq-connection nil)

(pq:chain (pq-connect)
  (pq:then (conn) (setq pq-connection conn))
  (pq:catch (err)
    ;; somehow handle error
    ))

;; but you need to make sure pq-connection is already resolved.
(pq:with pq-connection
  (pq:query '("SELECT version()") (row)
    (message "%s" row)))

Or, you can just store unresolved pq-future object.

(defvar pq-connection (pq-connect))

(pq:with pq-connection
  (pq:query '("SELECT version()") (row)
    (message "%s" row)))

todo lists

MD5 password authentication

SCRAM-SHA-256 password authentication is already implemented though.

Transaction API

For now, transaction can be done like this:

(pq:with-temp-conn nil
  (pq:exec "BEGIN")
  (pq:exec "INSERT INTO some_table VALUES ('value')")
  (pq:query '("SELECT * FROM some_table") (row)
    (message "%s" row))
  (pq:exec "COMMIT")) ;; or ROLLBACK