插入新行时，Android Room FOREIGN KEY约束失败(代码787)

问题描述

我关注了这篇帖子 Android Room FOREIGN KEY约束失败(代码787 ).不幸的是，对于我来说，它不起作用.

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

尝试插入新的记事时，我总是会收到错误消息.当然，数据库中存在一个主题.

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

你们有什么主意吗?

请在下面查看我的代码.

Please take a look at my code below.

主题:

@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
}

注意:

@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)
}

推荐答案

我发现了问题.因为我已经创建了2个不同的数据库:TopicDataBase和NoteDataBase.

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

所以我只需要删除其中1个即可.我的坏人><

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

这篇关于插入新行时，Android Room FOREIGN KEY约束失败(代码787)的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！