如何将现有的SQLite应用程序迁移到Room Persistance Library? [英] How to migrate existing SQLite application to Room Persistance Library?

问题描述

询问可能还为时过早，但是是否可能以及如何将现有的SQLite数据库应用程序迁移/升级到新的Android Room Persistance Library?

It might be a bit early to ask, but is it possible and how to migrate/upgrade an existing SQLite database application to a new Android Room Persistance Library?

推荐答案

假设您的房间实体与当前表模式匹配，则可以继续使用相同的数据库/表.

Assuming your room entities match your current table schemas, you can keep using the same database/tables.

Room管理一个主表，该主表在创建或升级数据库时初始化，因此您需要增加数据库版本并提供虚拟迁移:

Room manages a master table which is initialized on creation or upgrade of the database, so you need to increment your database version and provide a dummy migration:

@Database(entities = SomeEntity.class, version = EXISTING_VERSION + 1)
public class MyDatabase extends RoomDatabase {
    // ...
}

MyDatabase db = Room.databaseBuilder(context, MyDatabase.class, "db_name")
                    .addMigrations(new Migration(EXISTING_VERSION, EXISTING_VERSION + 1) {
                        @Override
                        public void migrate(SupportSQLiteDatabase database) {
                            // NOOP
                        }
                    }).build();

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