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Data migrations ​

You can easily generate data migrations for your database.

The data migrations are decoupled from your schema declaration, and you decide when to run them, before or after pushing your schema changes.

Generate a data migration ​

Generate a data migraion file with data scaffold command:

bash
npx monolayer-pg data scaffold

The data migration file exports two functions:

A Kysely client for the database is made available but you can import and use the client of your choice inside the function.

Applying data migrations ​

You can apply all pending data migrations with data apply command:

bash
npx monolayer-pg data apply

You can apply a single pending data migrations with data up command:

bash
npx monolayer-pg data up

Reverting data migrations ​

You can revert an applied data migration with data down command:

bash
npx monolayer-pg data down

Data migrations groups ​

By default, data migrations are placed and run in the data folder for your defined database: monolayer/[database-id]/data/.

Data migrations groups allows you to create different sets of data migrations that you can apply independently from each other.

You can create and use data migrations groups by using -g option on CLI commands.

Example ​

Let's say you want to have two sets of data migrations:

  • One set to apply before pushing schema changes.
  • Another set to apply after pushing schema changes.

Before group ​

bash
# Scaffold a data migration file in monolayer/[database-id]/data/before
npx monolayer-pg data scaffold -g before

# Revert a data migrations in monolayer/[database-id]/data/before
npx monolayer-pg data up -g before

# Apply data migrations in monolayer/[database-id]/data/before
npx monolayer-pg data down -g before

# Get the data migrations status in monolayer/[database-id]/data/before
npx monolayer-pg data status -g before

After group ​

bash
# Scaffold a data migration file in monolayer/[database-id]/data/after
npx monolayer-pg data scaffold -g after

# Revert a data migrations in monolayer/[database-id]/data/after
npx monolayer-pg data up -g after

# Apply data migrations in monolayer/[database-id]/data/after
npx monolayer-pg data down -g after

# Get the data migrations status in monolayer/[database-id]/data/after
npx monolayer-pg data status -g after