Hi :android-wave: I’m trying to do something on SQ...

# squarelibraries

[Matheus Finatti]

Hi 👋
I’m trying to do something on SQLDelight (using latest version on KMM project) but it’s not working, I’m not sure if this isn’t supported or I’m doing something wrong. I have something like this, just 2 tables to store userId <-> groupId relationship and one to store members, which has a groupId column.
I’m trying to flatMap one query into the other, but if I insert a new group under that userId it doesn’t trigger the chain.
small example:

suspend fun getGroups(userId: String): Flow<List<Groups>> =
    userGroupQueries.getGroups(userId)
        .asFlow()
        .mapToList(coroutineContext)
        .flatMapLatest { groupIds: List<String> -> 
            memberQueries.getAllGroupsMembers(groupIds)
                .asFlow()
                .mapToList(coroutineContext)
                .mapLatest { members -> members.groupBy { it.groupId }}
        }

UserGroup.sq
CREATE TABLE UserGroup(
    userid TEXT NOT NULL,
    groupid TEXT NOT NULL,
    FOREIGN KEY (groupid) REFERENCES EGroup(id),
    FOREIGN KEY (userid) REFERENCES User(id)
);

getGroups:
SELECT groupid FROM UserGroup WHERE userid = ?;

Member.sq
getAllFromGroupIds:
SELECT * FROM Member WHERE groupid IN ?;

I can try to provide a minimum reproducible example if necessary. Didn’t find anything like this on SO or on github so I wonder if I’m trying to do something silly

[glureau]

Why getting a Flow if you just want the latest? I'm worried you're waiting for a Flow to complete here, and it probably won't since it listen the DB changes.
(Also I'm presume it could be a sql join for performance)

[Matheus Finatti]

I don’t know 🤔, I kinda expected to be notified if somewhere along the chain a query emits, like if the user has a new group or a group new members.

[Matheus Finatti]

In the end all I do is map it to a domain model like Group(id: String, members: List<Member>) so maybe this whole ordeal is indeed unnecessary

[glureau]

You're listening 2 differents tables, but not at the same time. If the 1st request emit something, you'll start listening the second one. Let's say the 1st request emit a 2nd time, you'll start another listener on the 2nd request.

[glureau]

If you do an inner join in sql, you'll be able to listen for what you want.

[Matheus Finatti]

Thanks, that makes sense.