Database migrations

Database migrations and setup scripts must be located in the reserved folder db/migrations.

TypeORM migrations

The Squid SDK offers first-class support for TypeORM-based database migrations with the squid-typeorm-migration(1) tool. The tool auto-generates the schema migrations from the TypeORM entities created by codegen so that custom migration scripts are rarely needed.

Most use cases of the tool are covered by the pre-defined sqd commands that wrap around squid-typeorm-migration. From sqd --help:

sqd migration:apply    Apply the DB migrations
sqd migration:generate Generate a DB migration matching the TypeORM entities
sqd migration:clean    Clean the migrations folder

To inspect the full list of available options, run

npx squid-typeorm-migration --help

To generate or update the migrations after a schema change, follow the steps below.

Updating after schema changes

In most cases the simplest way to update the schema is to drop the database and regenerate the migrations from scratch.

1. Update schema.graphql

2. Regenerate the TypeORM entity classes and build the squid with

# generate entites from the schema file
sqd codegen
sqd build

3. Recreate the database and remove the old migrations

# drop the database
sqd down
# wipe out old migrations
sqd migration:clean
# start a blank database
sqd up

Note that without dropping the database the next step will generate a migration only for the schema difference.

4. Create the new database migration

# generate new scripts in db/migrations
sqd migration:generate

5. Apply the database migration

# apply the migrations
sqd migration:apply

Updating a deployed squid schema

In some rare cases it is possible to update the schema without dropping the database and restarting the squid from a blank state. The most important case is adding an index to an entity field. More complex changes are usually not feasible.

1. Update schema.graphql

For example, add an index

2. Regenerate the model classes

sqd codegen
sqd build

3. Create new database migration

Make sure the local database is running.

sqd up
sqd migration:generate

4. Apply the database migration

Inspect the new migration in db/migrations and apply it:

sqd migration:apply

5. Update the squid in Aquairum

If the squid is deployed to Aquarium, update the deployed version.

Aquarium deployment

By default, the TypeORM migrations are automatically applied by Aquarium with the command npx squid-typeorm-migration apply before the squid services are started. For custom behavior, one can override the migration script using the optional migrate: section of squid.yaml.

info

To force Aquarium to reset the database and start with a blank state after a schema change, use the --hard-reset flag of sqd deploy.