Recovering lost migrations​

Each time you create a migration with edgedb migration create, a file containing the DDL for that migration is created in dbschema/migrations. When you apply a migration with edgedb migration apply or edgedb migrate, the database stores a record of the migration it applied.

On rare occasions, you may find you have deleted your migration files by mistake. If you don’t care about any of your data and don’t need to keep your migration history, you can wipe your database and start over, creating a single migration to the current state of your schema. If that’s not an option, all hope is not lost. You can instead recover your migrations from the database.

Run this query to see your migrations:

select schema::Migration {
  name,
  script,
  parents: {name}
}

You can rebuild your migrations from the results of this query, either manually or via a script if you’ve applied too many of them to recreate by hand. Migrations in the file system are named sequentially starting from 00001.edgeql. They are in this format:

CREATE MIGRATION m1rsm66e5pvh5ets2yznutintmqnxluzvgbocspi6umd3ht64e4naq
                 # ☝️ Replace with migration name
    ONTO m1l5esbbycsyqcnx6udxx24riavvyvkskchtekwe7jqx5mmiyli54a
         # ☝️ Replace with parent migration name
{
  # script
  # ☝️ Replace with migration script
};

or if this is the first migration:

CREATE MIGRATION m1l5esbbycsyqcnx6udxx24riavvyvkskchtekwe7jqx5mmiyli54a
                 # ☝️ Replace with migration name
    ONTO initial
{
  # script
  # ☝️ Replace with migration script
};

Replace the name, script, and parent name with the values from your Migration query results.

You can identify the first migration in your query results as the one with no object linked on parents. Order the other migrations by chaining the links. The Migration with the initial migration linked via parents is the second migration — 00002.edgeql. The migration linking to the second migration via parents is the third migration, and so on).