Saving to PostgreSQL and compatible databases

TypeormDatabase context store provides a wrapper over the TypeORM EntityManager optimized for batch saving. It currently supports only Postgres-compatible databases and seamlessly integrates with entity classes generated from the schema file.

Check out this section of the reference page to learn how to specify the database connection parameters.

Usage

import { Store, TypeormDatabase } from '@subsquid/typeorm-store'
import { FooEntity } from './model'

const dbOptions = {/* ... constructor options ... */}

processor.run(new TypeormDatabase(dbOptions), async ctx => {
  // ...  
  await ctx.store.upsert([new FooEntity({ id: '1'}), new FooEntity({ id: '2'})])
})

Here,

• FooEntity represents a TypeORM entity class. In squids, these are typically generated from schema files with squid-typeorm-codegen.
• TypeormDatabase constructor options govern the behavior of the class at the highest level. They are described in this section of the reference.
• ctx.store is of type Store. See the Store interface section of the reference page for more details.

Database migrations

The Squid SDK manages the database schema with TypeORM-based database migrations by means of 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.

Here are some useful commands:

npx squid-typeorm-migration apply # Apply the DB migrations

npx squid-typeorm-migration generate # Generate a DB migration matching the TypeORM entities

rm -r db/migrations # Clean the migrations folder

Inspect the full list of available options with

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

# generate entites code from the schema file
npx squid-typeorm-codegen

3. Recreate the database

# drop the database
docker compose down

# start a blank database
docker compose up -d

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

4. Build the squid code

npm run build

5. Recreate the database migration

rm -r db/migrations

npx squid-typeorm-migration generate

6. Apply the database migration

npx squid-typeorm-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 and build the code

npx squid-typeorm-codegen
npm run build

3. Create a new database migration

Make sure the local database is running.

docker compose up -d
npx squid-typeorm-migration generate

4. Apply the database migration

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

npx squid-typeorm-migration apply

5. Update the squid in Cloud

If the squid is deployed to Subsquid Cloud, update the deployed version.

Subsquid Cloud deployment

By default, the TypeORM migrations are automatically applied by Cloud 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 Cloud to reset the database and start with a blank state after a schema change, use the --hard-reset flag of sqd deploy.