如果在Room数据库中添加了新表，是否需要添加迁移？

Question

I have two tables,person is already existing(added column userid as foreign key)

    @Entity(tableName = TABLE_NAME)
    data class Person(
    @PrimaryKey @ColumnInfo(name = CLIENT_ID) var id: Long,
    @ColumnInfo(name = USER_ID)var userId : Int = 1) : Parcelable {}

this is the newly added class,which has foreign key of person class(userid)

    @Entity(tableName = Profile.TABLE_NAME,
    foreignKeys = [ForeignKey(entity= Person::class,
    parentColumns = [(Person.USER_ID)],
    childColumns = [(Profile.USER_ID)],
    onDelete = ForeignKey.CASCADE)])
    @Parcelize
    data class Profile(@PrimaryKey(autoGenerate = true)
    var userId: Int,
    var name: String? = null):Parcelable{}

Here i have two tables in the DB. Now,do i need to write migration code for creation of new table?

Answer 1

If you want to migrate your data from the previous version to the new version then

Yes. You have to write the migration code.

If you only want to migrate schema and not data. then no need to write migration logic. Just add fallbackToDestructiveMigration() in Room builder.

Example:

Room.databaseBuilder(appContext, AppDatabase.class, AppDatabase.DATABASE_NAME)
            .fallbackToDestructiveMigration()
            .build();