使用现有的布尔列类型进行房间迁移

使用值和as 定义新属性 newAttribute 的迁移。

DEFAULT``NOT NULL

码

database.execSQL("ALTER TABLE tableName ADD COLUMN newAttribute INTEGERDEFAULT 0 NOT NULL")

完整代码

@Database(entities = arrayOf(ModelName::class), version = 2)@TypeConverters(Converters::class)abstract class DatabaseName : RoomDatabase() {    abstract fun daoname(): Daoname    companion object {        private var INSTANCE: DatabaseName? = null        fun getAppDatabase(context: Context): DatabaseName { if (INSTANCE == null) {     INSTANCE = Room.databaseBuilder(context.applicationContext,  DatabaseName::class.java, DATAbase_NAME)  .addMigrations(MIGRATION_1_2)  .build() } return INSTANCE as DatabaseName        }        val MIGRATION_1_2: Migration = object : Migration(1, 2) { override fun migrate(database: SupportSQLiteDatabase) {     database.execSQL("ALTER TABLE tableName ADD COLUMN newAttribute INTEGER DEFAULT 0 NOT NULL") }        }    }}