房间自动迁移没有这样的列：column_name（代码1 SQLITE_ERROR）：，编译时：INSERT INTO

Question

我尝试通过添加新字段来更新我的 Room 实体：

版本1：

@Entity(tableName = TABLE_NAME)
data class AvailableAccountRoom(
    @PrimaryKey
    val id: String = "",
    [...]
)

版本2：

@Entity(tableName = TABLE_NAME)
data class AvailableAccountRoom(
    @PrimaryKey
    val id: String = "",
    [...]
    val isExchangeSupported: Boolean,
)

我想使用自动迁移，所以我也将此行添加到我的数据库中：

autoMigrations = [
   AutoMigration(from = 1, to = 2)
]

但是我在运行时崩溃并显示下一条消息：

(1) no such column: isExchangeSupported in "INSERT INTO `_new_table_name` (`id`,`isExchangeSupported`
(1) no such column: isExchangeSupported in "INSERT INTO `_new_table_name` (`id`,`isExchangeSupported`
FATAL EXCEPTION: OkHttp Dispatcher
                 Process: ...
                 android.database.sqlite.SQLiteException: no such column: isExchangeSupported (code 1 SQLITE_ERROR): , while compiling: INSERT INTO
                 `_new_table_name` (`id`,`isExchangeSupported`) SELECT
                 `id`,`isExchangeSupported` FROM
                 `table_name `
                    at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
                    at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:1068)
                    at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:673)
                    at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:590)
                    at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:62)
                    at android.database.sqlite.SQLiteStatement.<init>(SQLiteStatement.java:34)
                    at android.database.sqlite.SQLiteDatabase.executeSql(SQLiteDatabase.java:2086)
                    at android.database.sqlite.SQLiteDatabase.execSQL(SQLiteDatabase.java:2008)
                    at androidx.sqlite.db.framework.FrameworkSQLiteDatabase.execSQL(FrameworkSQLiteDatabase.kt:246)
                    at com.###.AppDatabase_AutoMigration_1_2_Impl.migrate(AppDatabase_AutoMigration_1_2_Impl.java:18)
                    at androidx.room.RoomOpenHelper.onUpgrade(RoomOpenHelper.kt:91)
                    at androidx.sqlite.db.framework.FrameworkSQLiteOpenHelper$OpenHelper.onUpgrade(FrameworkSQLiteOpenHelper.kt:253)
                    at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:416)
                    at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:316)
                    at androidx.sqlite.db.framework.FrameworkSQLiteOpenHelper$OpenHelper.getWritableOrReadableDatabase(FrameworkSQLiteOpenHelper.kt:232)
                    at androidx.sqlite.db.framework.FrameworkSQLiteOpenHelper$OpenHelper.innerGetDatabase(FrameworkSQLiteOpenHelper.kt:190)
                    at androidx.sqlite.db.framework.FrameworkSQLiteOpenHelper$OpenHelper.getSupportDatabase(FrameworkSQLiteOpenHelper.kt:151)
                    at androidx.sqlite.db.framework.FrameworkSQLiteOpenHelper.getWritableDatabase(FrameworkSQLiteOpenHelper.kt:104)
                    at androidx.room.RoomDatabase.inTransaction(RoomDatabase.kt:638)
                    at androidx.room.RoomDatabase.assertNotSuspendingTransaction(RoomDatabase.kt:457)
                    at androidx.room.RoomDatabase.query(RoomDatabase.kt:486)
                    at androidx.room.util.DBUtil.query(DBUtil.kt:75)
                    at com.###Dao_Impl$6.call(LoginTokenDao_Impl.java:156)
                    at com.###Dao_Impl$6.call(LoginTokenDao_Impl.java:153)
                    at androidx.room.CoroutinesRoom$Companion$execute$4$job$1.invokeSuspend(CoroutinesRoom.kt:88)
                    at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)

我还尝试在实体中指定新字段的默认值：

val isExchangeSupported: Boolean = false,

但是我也有同样的错误

我做错了什么？ 一般来说，我只需要迁移一个不改变的表，其余的可以删除，但我没有找到一种方法来做到这一点，所以我使用自动迁移。但这是行不通的。 任何解决方案都会对我有好处，提前谢谢

Answer 1

对于任何可能遇到同样问题的人，

观察：如果您在增加数据库版本之前构建应用程序，则可能会发生这种情况，当 room 然后尝试进行迁移时，源 JSON 模式将被解释为与目标 JSON 模式相同

解决方案：修改源 JSON 架构以匹配旧版本，然后重做构建，或者如果您将其置于版本控制之下，则只需重置为提交的版本

注意：通过 JSON 模式，我指的是由 room 定义数据库模式自动生成的 JSON 文件