Overview

Nomad is a SQL schema migration library. It uses pure Clojure functions to implement forward migrations (rollback migrations are a planned feature).

Usage

Add below git coordinates in deps.edn

omnyway-labs/nomad
{:git/url "https://github.com/omnyway-labs/nomad.git",
 :sha "8af037d2cafeb3bf48cca804493ad8d43b74da7e"}

Define migration handlers as follows:

(require '[nomad.core :as nomad :refer [defmigration]])
(require '[clojure.java.jdbc :as jdbc])

(defmigration initial-schema
  :up   (fn []
          (jdbc/do-commands
           "CREATE TABLE test(name VARCHAR(32))")))

(defmigration add-age-column
  :up   (fn []
          (jdbc/do-commands
           "ALTER TABLE test ADD COLUMN age INTEGER")))

The name of the migration is used as a unique identifier and is used to track whether the migration has already been applied.

To apply a set of migrations Nomad requires a migrator to be provided - see nomad-migrators for a list of currently implemented migrators (H2 and Postgres). Migrators provide concrete implementations of the IMigrator protocol, which specifies function entry points for loading and saving migration state.

(require '[nomad.migrator.h2 :as h2])

;; create a migrator
(def migrator (h2/connect {:db "mem:test;DB_CLOSE_DELAY=-1;IGNORECASE=TRUE"}))

;; apply migrations
(nomad/migrate! migrator)
16-08-06 19:11:19 luna INFO [nomad.core:89] - Applying migration init-schema
16-08-06 19:11:19 luna INFO [nomad.core:89] - Applying migration add-test1-age

References

See nomad-migrators for examples of how to create migrators for different databases.