Create or update record (batch)

Hey, guys.

What is the proper way of create or updating records in one statement? I fetch the updated data and I need to save into the database. I understand all validation must be made on javascript and that makes us to do try/catch everywhere.

await database.action(async () => {
  const postsCollection = database.collections.get('posts')
  try {
    // try to find post by id
    const post = await postsCollection.find('abcdef')
    // if it exists, update it
    await somePost.update(post => {
      post.title = 'Updated title'
    })
  } catch (error) {
    // if post was not found, create it
    const newPost = await postsCollection.create(post => {
      post.title = 'New post'
      post.body = 'Lorem ipsum...'
    })
  }
})

A bit verbose, but it works. This is for one record, but the server returns 20 records, so it’s not optimal. We need batch then.

let statements = [
  database.action(async () => {
    const postsCollection = database.collections.get('posts')
    try {
      // try to find post by id
      const post = await postsCollection.find('abcdef')
      // if it exists, update it
      somePost.prepareUpdate(post => {
        post.title = 'Updated title'
      })
    } catch (error) {
      // if post was not found, create it
      const newPost = postsCollection.prepareCreate(post => {
        post.title = 'New post'
        post.body = 'Lorem ipsum...'
      })
    }
  })
]
database.batch(statements);

The code above raises an error. I’m not sure why 🤔

Note: In Realm, this can be achieved this way:

realm.write(() => {
  // just pass `true` as third argument
  realm.create('Post', {id: 1, title: 'New post', body: 'Lorem ispum'}, true);
});

https://realm.io/docs/javascript/latest/#creating-and-updating-objects-with-primary-keys

cc @radex

[radex]

This:

const actions = [
  database.action(async () => {
     // ...
  })
]
await Promise.all(actions);
await database.batch(...operations);

is misguided. batch must be called within an Action — but you don’t have to do one Action per operation — doesn’t really make sense. An Action ought to encompass all related operations, and your finds, created, and updates are related.

Here’s how you create or update multiple records in one go efficiently (yes, it’s not the prettiest code and could be a bit easier, but should work unless I misunderstand your problem):

database.action(async () => {
  // check which posts already exist
  const existingPosts = await database.collections.get('posts').query(Q.where('id', Q.oneOf(['abcdef', 'dasdasd', 'asdasd'])))

  const postsToCreate = IDs that are not contained in existingPosts
  const poststoUpdate = Posts that are contained in existing Posts

 await database.batch(
   ...postsToUpdate.map(post => post.prepareUpdate(() => {
     post.title = 'Updated title'
   })),
   ... postsToCreate.map(postData => collection.prepareCreate(post => {
    post.title = 'New title'
  }))
 )
})

Does this make sense to you?

[Acetyld]

Is there any update on this?. A upsert/ merge function?