How get the last element in the table in the relationship in an efficient way?

Question

let's say I have an entity called user and each user has many accounts, and I want to get the last account inserted in a specific user.

I tried different solutions but I didn't find a better one, I had to get a user and then use loadItems method with orderBy desc and then get first element but I don't want to load all accounts from DB.

that's what I did

const user = await this.repository.find({id})
const accounts = await user.accounts.loadItems({orderBy: {['column']: 'DESC'}})

return accounts[0];

that's absolutely not a good solution because I load all items from the database first, is there any other way to do it? I'm still new in MikroOrm so I'll appreciate any suggestions.

Thanks in advance.

Answer 1

There are many options:

• use em.findOne to load just the right entity (e.g. em.findOne(Account, { user }))
• use user.accounts.matching that has a limit option: https://mikro-orm.io/docs/collections#filtering-collections
• if you want to do this for many entities and not just one, use SQL sub query via @Formula decorator: https://mikro-orm.io/docs/defining-entities#formulas