Schema Migration

Zorix handles structural changes to your database automatically whenever you increment the database version. For complex structural changes, it provides a powerful declarative migration API.

Automatic Actions

When you initialize a DB with a higher version number, Zorix automatically:

• Creates New Stores: If a model is defined for a store that doesn't exist.
• Adds New Indexes: Based on your schema definitions.
• Deletes Removed Indexes: To optimize storage space.

const db = new DB('my-app', { version: 2 });

Declarative Migrations

For specific structural operations like deleting a store or manually managing indexes during an upgrade, use the migrate() method.

db.migrate({
  // Perform structural changes on the 'users' table
  users(table) {
    table.createIndex('email', 'email', {
      unique: true,
    });

    // Clean up old indexes
    table.deleteIndex('oldEmail');
  },

  // Delete an entire object store by setting it to null
  deprecated_logs: null,
});

IMPORTANT

• migrate() must be called before opening the database or defining models if you want the changes to be applied during the initial upgrade.

Migration Table API

The table object passed to your migration function provides:

Method	Description
createIndex(name, keyPath, options)	Adds a new index to the store.
deleteIndex(name)	Removes an existing index.

Changing Field Types

If you change a field type in your schema (e.g., from string to number), Zorix won't automatically convert the existing data. To transform data, see the Data Transformation guide.

NOTE

When performing data transformations, keep in mind that the records are treated as any type. This is intentional, as the data being transformed often originates from an older, incompatible schema version.

Learn more about Versioning.