Model a Room one-to-many Playlist-to-Song relationship
Tests Room relational modeling. Strong answer: Song foreign key, `@Embedded` Playlist with `@Relation` to `List<Song>`, DAO wrapped in `@Transaction`. Red flag: embedding songs in Playlist or skipping `@Transaction`, which causes N+1 queries.
Tests your understanding of Room relational modeling without violating normalization. A complete answer: define separate entities with a foreign key on `Song` referencing `playlistId`; create a data class with `@Embedded val playlist: Playlist` and `@Relation(parentColumn = "id", entityColumn = "playlistId") val songs: List<Song>`; expose a DAO method returning this class annotated with `@Transaction` to force an efficient join instead of N+1 queries; and index the foreign key.
Read the original → developer.android.com
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- #room
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- #kotlin
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