Hey! :wave: In realtime, specifying the primary ke...

# supabase-kt

[Nacho Ruiz Martin]

Hey! 👋
In realtime, specifying the primary key of the listened table is needed.
1. Why is this a need?
2. How can a multi-column PK be passed?

[Nacho Ruiz Martin]

Is something like this correct?

.selectAsFlow<PubAdmin>(
    PrimaryKey("pub_admin") { it.user + it.pub },
    filter = FilterOperation("user", FilterOperator.EQ, userId)
)

[Jan]

The primary key is used for local caching because realtime doesn't send over all the rows matching the filter on a database update. You specify two things with this parameter: 1. the actual column name like "product_id" which is used for the DELETE event and 2. a producer to get the value of the primary key once the updated object has been serialized. As of now, there is no way to pass a multi-column PK. It may be possible though if you add the possibility to provide a list of primary keys and use a concatinated string of all primary keys as the key for the cache?

[Nacho Ruiz Martin]

Sorry, I didn’t come back to you.

It may be possible though if you add

You mean to add this in the SDK, right?

[Jan]

Yes.

[Nacho Ruiz Martin]

I’ll take a look 🙂, thanks!

[Jan]

Yea I think its best to have the base method with a list of primary keys and all other existing methods are just overloads calling selectAsFlow(listOf(primaryKey)) . With that, there are no big breaking changes needed

[Nacho Ruiz Martin]

That sounds like a good strategy 🙂. Let me open a PR with it.