👀 Views: 21 💬 Answers: 1 📅 Created: 2025-09-06

android room sqlite kotlin

I can't seem to get I'm having trouble with I'm working on a personal project and Quick question that's been bugging me - While refactoring an existing Android application to use Room for database management, I'm struggling with migration of a local SQLite database that has multiple complex relationships. This legacy application currently uses raw SQL queries to handle a user profile that links to several other tables, including user settings and activity logs. My goal is to transition to Room without losing existing data. I followed the official Room documentation to create entities for each table: ```kotlin @Entity(tableName = "user_profile") data class UserProfile( @PrimaryKey val userId: Long, val username: String, val email: String ) @Entity(tableName = "user_settings") data class UserSettings( @PrimaryKey val settingId: Long, val userId: Long, val notificationsEnabled: Boolean ) @Entity(tableName = "activity_logs") data class ActivityLog( @PrimaryKey val logId: Long, val userId: Long, val activity: String, val timestamp: Long ) ``` Then, I set up the relationships using the `@Relation` annotation: ```kotlin data class UserWithSettingsAndLogs( @Embedded val userProfile: UserProfile, @Relation( parentColumn = "userId", entityColumn = "userId" ) val userSettings: List<UserSettings>, @Relation( parentColumn = "userId", entityColumn = "userId" ) val activityLogs: List<ActivityLog> ) ``` After configuring the DAO, I implemented a migration script to retain existing data but ran into several challenges. The migration SQL looks like this: ```kotlin val MIGRATION_1_2 = object : Migration(1, 2) { override fun migrate(database: SupportSQLiteDatabase) { // Create new tables database.execSQL("CREATE TABLE user_profile ...") // Copy data from old tables database.execSQL("INSERT INTO user_profile (...) SELECT ... FROM old_user_profile") // Handle foreign keys or relationships } } ``` Even though my migration script compiles, it seems that some relationships are not being handled properly, leading to `SQLiteConstraintException` errors when I try to query the data after migration. I've also checked the integrity of the foreign key constraints but still find inconsistencies. Any suggestions on best practices for migrating complex relationships to Room while ensuring data integrity? Or is there a better approach to address the migration without data loss? Any suggestions would be helpful. I'd love to hear your thoughts on this.