android room migrations

要开启 

exportSchema = true

 

 

 

迁移测试

导入：room-testing

错误

androidx.test.ext 报错  Failed to resolve: androidx.test.ext:junit:1.3.0

去掉：androidx.test.ext 的版本号，version.ref = "junitVersion" ，由composeBom 决定版本

测试代码

package cn.shaoyangwl.database_room_migrationimport android.content.Context
import androidx.room.Room
import androidx.room.testing.MigrationTestHelper
import androidx.sqlite.db.framework.FrameworkSQLiteOpenHelperFactory
import androidx.test.core.app.ApplicationProvider
import androidx.test.ext.junit.runners.AndroidJUnit4
import androidx.test.platform.app.InstrumentationRegistry
import cn.shaoyangwl.database_room_migration.database.TestDatabase
import cn.shaoyangwl.database_room_migration.database.dao.ArticleDao
import cn.shaoyangwl.database_room_migration.database.dao.UserDao
import cn.shaoyangwl.database_room_migration.database.entity.Article
import cn.shaoyangwl.database_room_migration.database.entity.User
import com.google.common.truth.Truth.assertThat
import org.junit.After
import org.junit.Before
import org.junit.Rule
import org.junit.Test
import org.junit.runner.RunWith
import java.io.IOException@RunWith(AndroidJUnit4::class)
class MigrationTest {private val TEST_DB = "migration-test"@get:Ruleval helper: MigrationTestHelper = MigrationTestHelper(InstrumentationRegistry.getInstrumentation(),
//        MigrationDb::class.java.canonicalName,TestDatabase::class.java,listOf(),FrameworkSQLiteOpenHelperFactory())@Test@Throws(IOException::class)fun migrate1To2() {var db = helper.createDatabase(TEST_DB, 2).apply {// Database has schema version 1. Insert some data using SQL queries.// You can't use DAO classes because they expect the latest schema.execSQL("INSERT INTO user (first_name,last_name)  VALUES('test@test.com', 'Philipp')");execSQL("INSERT INTO user (first_name,last_name)  VALUES('first_name', 'test')");val cursor = query("select * from user")while (cursor.moveToNext()){val id = cursor.getInt(0)val name = cursor.getString(1)val lastName = cursor.getString(2)println("id:$id,name;$name,lastName:$lastName")}println("ok")// Prepare for the next version.
            close()}println("ok-ok")db = helper.runMigrationsAndValidate(TEST_DB, 2, true)db.query("SELECT * FROM user").apply {assertThat(moveToFirst()).isTrue()println(moveToFirst())println(getLong(getColumnIndex("id")))
//            assertThat(getLong(getColumnIndex("id"))).isEqualTo(0)
        }// Re-open the database with version 2 and provide// MIGRATION_1_2 as the migration process.
//        db = helper.runMigrationsAndValidate(TEST_DB, 2, true, TestDatabase.MIGRATION_1_2)// MigrationTestHelper automatically verifies the schema changes,// but you need to validate that the data was migrated properly.
    }@Testfun testAllMigrations() {helper.createDatabase(TEST_DB, 1).apply { close() }Room.databaseBuilder(InstrumentationRegistry.getInstrumentation().targetContext,TestDatabase::class.java,TEST_DB).addMigrations(TestDatabase.MIGRATION_3_4, TestDatabase.MIGRATION_4_5).build().apply {openHelper.writableDatabase.close()}println("testAllMigrations ok")}
}@RunWith(AndroidJUnit4::class)
class SimpleEntityReadWriteTest {private lateinit var userDao: UserDaoprivate lateinit var articleDao: ArticleDaoprivate lateinit var db: TestDatabase@Beforefun createDb() {val context = ApplicationProvider.getApplicationContext<Context>()db = Room.inMemoryDatabaseBuilder(context, TestDatabase::class.java).addMigrations(TestDatabase.MIGRATION_3_4, TestDatabase.MIGRATION_4_5).build()userDao = db.userDao()articleDao = db.articleDao()
//        userDao.getAll().forEach(::println)
    }@After@Throws(IOException::class)fun closeDb() {db.close()}@Test@Throws(Exception::class)fun writeUserAndReadInList() {
//        val user: User = TestUtil.createUser(3).apply {
//            setName("george")
//        }val user = User(null, "11", "44")userDao.insertAll(user)val userList = userDao.getAll()userList.forEach(::println)val article = Article(null,"hi","content1","test")val article2 = Article(null,"hi2","content1","test")articleDao.insertAll(article,article2)articleDao.getAll().forEach(::println)
//        assertThat(byName.get(0), equalTo(user))
    }
}

TestDatabase 代码

package cn.shaoyangwl.database_room_migration.databaseimport androidx.room.AutoMigration
import androidx.room.Database
import androidx.room.RoomDatabase
import androidx.room.migration.Migration
import androidx.sqlite.db.SupportSQLiteDatabase
import cn.shaoyangwl.database_room_migration.database.dao.ArticleDao
import cn.shaoyangwl.database_room_migration.database.dao.FruitDao
import cn.shaoyangwl.database_room_migration.database.dao.UserDao
import cn.shaoyangwl.database_room_migration.database.entity.Article
import cn.shaoyangwl.database_room_migration.database.entity.Fruit
import cn.shaoyangwl.database_room_migration.database.entity.User@Database(entities = [User::class, Article::class, Fruit::class], version = 5, exportSchema = true, autoMigrations = [ AutoMigration(from = 1, to = 2), AutoMigration(from = 2, to = 3)])
abstract class TestDatabase : RoomDatabase() {abstract fun userDao(): UserDaoabstract fun fruitDao(): FruitDaoabstract fun articleDao(): ArticleDaocompanion object{val MIGRATION_1_2 = object : Migration(1, 2) {override fun migrate(db: SupportSQLiteDatabase) {db.execSQL("CREATE TABLE `Fruit` (`id` INTEGER, `name` TEXT, " +"PRIMARY KEY(`id`))")}}val MIGRATION_3_4 = object : Migration(3, 4) {override fun migrate(db: SupportSQLiteDatabase) {db.execSQL("CREATE TABLE IF NOT EXISTS `article` (`id` INTEGER, `title` TEXT, `content` TEXT," +"PRIMARY KEY(`id`))")}}val MIGRATION_4_5 = object : Migration(4, 5) {override fun migrate(db: SupportSQLiteDatabase) {db.execSQL("alter table article add column author text")}}}}

　　参考文档：https://developer.android.com/training/data-storage/room/migrating-db-versions#kotlin_1