Migrations

Shipclojure uses migratus to handle migrations. For ease of creating migrations, there is the migrations namespace

Store

By default, ShipClojure stores migrations in a table in the main DB

See db.sql/migrations key in system.edn

Creating a migration

Let's say you need to create a new image table in the DB to store user images.

1. Visit migrations.clj

2. In the last comment, you'll see imported the migration-config from user

3. Write in the same comment

  (create-migration (migration-config) "add-images-table" :sql)

1. Evaluate this in the REPL

2. Expect to see 2 new files {current-date}-add-images-table.{up,down}.sql in resources/db/migrations

3. Add the correct up & down configurations, and reset the integrant system. The migrations will be applied automatically

Important: If you want to include multiple statements in the same migration file there is a special notation (--;;) you need to use, otherwise you'll get an error Too many update results were returned:

ALTER TABLE user_account
    DROP COLUMN IF EXISTS image_url;
--;;
CREATE TABLE user_image (
    id TEXT NOT NULL PRIMARY KEY,
    alt_text TEXT,
    content_type TEXT NOT NULL,
    blob BYTEA NOT NULL,
    created_at TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
    user_id TEXT NOT NULL REFERENCES user_account(id) ON DELETE CASCADE ON UPDATE CASCADE
);
--;;
CREATE UNIQUE INDEX user_image_user_id_idx ON user_image(user_id);

Rolling back migrations

To roll back migrations, use user/rollback-latest-migration