Android Room FOREIGN KEY constraint failed (code 7

Question

I followed this post Android Room FOREIGN KEY constraint failed (code 787). Unfortunately, it not works in my case.

I always get the error when trying to insert a new Note. Of course, there is a Topic existed in Database.

Do you guys have any idea?

Please take a look at my code below.

Topic:

@Entity(tableName = "topic")
data class Topic(@PrimaryKey var id: Long? = null,
            @ColumnInfo(name = "name") var name: String,
            @ColumnInfo(name = "note_count") var noteCount: Int = 0,
            @ColumnInfo(name = "view_count") var viewCount: Long = 0) : Serializable {
    @Ignore
    var notes: List<Note>? = null
}

Note:

@Entity(tableName = "note",
        foreignKeys = arrayOf(ForeignKey(entity = Topic::class,
        parentColumns = arrayOf("id"), childColumns = arrayOf("topic_id"), onDelete = ForeignKey.CASCADE)))
@TypeConverters(TimestampConverter::class)
data class Note(@PrimaryKey(autoGenerate = true) var noteId: Long? = null,
           @ColumnInfo(name = "topic_id") var topicId: Long? = null,
           @ColumnInfo(name = "title") var title: String,
           @ColumnInfo(name = "caption") var caption: String? = "",
           @ColumnInfo(name = "created_at") var createdAt: Date? = null) : Serializable {

}

NoteDao:

@Dao
interface NoteDao {
    @Query("SELECT * from note")
    fun getAll(): LiveData<List<Note>>

    @Insert(onConflict = REPLACE)
    fun insert(note: Note)

    @Query("DELETE from note")
    fun deleteAll()

    @Delete
    fun delete(category: Note)

    @Query("SELECT * FROM note WHERE title = :title COLLATE NOCASE LIMIT 1")
    fun findNoteByTitle(title: String): Note?

    @Query("SELECT * FROM note WHERE topic_id = :topicId")
    fun findNotesByTopicId(topicId: Long): LiveData<List<Note>>

    @Query("SELECT count(*) FROM note WHERE topic_id = :topicId")
    fun countNotesByTopicId(topicId: Long): Long

    @Update(onConflict = IGNORE)
    fun update(category: Note)
}

Answer 1

(@PrimaryKey var id: Long? = null, looks like a problem. Primary key can't be null

Answer 2

I found the problem. Because I have been created 2 different Databases: TopicDataBase and NoteDataBase.

So I just need to remove 1 of them. My bad >"<