我关注了这篇文章Android Room FOREIGN KEY constraint failed (code 787)。不幸的是，它不适用于我的情况。
尝试插入新注释时，我总是收到错误消息。当然，数据库中存在一个主题。
你们有什么想法吗？
请看下面我的代码。
话题：
@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
}
笔记：
@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 {
}
注道：
@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)
}