add ControlledTransaction.

[igalklebanov]

closes #257.

This PR adds some optional savepoint-related methods to drivers - need to make sure we don't introduce a breaking change here!
A new ControlledTransaction that allows manual commit, rollback and savepoint-related commands.

const trx = await db.startTransaction().execute()

try {
  const moshe = await trx
    .insertInto('person')
    .values({ name: 'Moshe' })
    .returning('id')
    .executeTakeFirstOrThrow()

  const trxAfterFoo = await trx.savepoint('foo').execute()

  try {
    const bone = await trxAfterFoo
      .insertInto('toy')
      .values({ name: 'Bone', price: 1.99 })
      .returning('id')
      .executeTakeFirstOrThrow()

    await trxAfterFoo
      .insertInto('pet')
      .values({ 
        owner_id: moshe.id, 
        name: 'Lucky', 
        favorite_toy_id: bone.id 
      })
      .execute()
  } catch (error) {
    await trxAfterFoo.rollbackToSavepoint('foo').execute()
  }

  await trxAfterFoo.releaseSavepoint('foo').execute()

  await trx.insertInto('audit').values({ action: 'added Moshe' }).execute()

  await trx.commit().execute()
} catch (error) {
  await trx.rollback().execute()
}

Some design goals (that hopefully will be met once this is done) with ControlledTransaction:

• allow starting a controlled transaction in single connection scenario - it should re-use the connection, and not close/release it on commit/rollback by default.
  - allow to release the connection on commit/rollback on demand via an option.
• once the controlled transaction is committed/rolled back, it should not allow executing any further queries with it.
• savepoint names are type-safe and autocompletion friendly - cannot release/rollback to a name that was not saved before. cannot save with a name that already exists.

[vercel]

The latest updates on your projects. Learn more about Vercel for Git ↗︎

Name	Status	Preview	Comments	Updated (UTC)
kysely	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Oct 5, 2024 4:53pm

[seivan]

I was wondering, since you already have a reference to the transaction trxAfterFoo and it has been named at creation with trx.savepoint('foo').execute() why not default to it

instead of

trxAfterFoo.rollbackToSavepoint('foo')

It should technically be enough with trxAfterFoo.rollbackToSavepoint() or am I missing something?

The reason I ask is because I'd like something simple like db.startTransaction() and db.endTransaction() to be in beforeEach and afterEach test, so each unit test runs with empty tables.