What database do you use in your projects?

Used several options depending on project requirements:

• Room Persistent Library: Most often. Provides a convenient abstract layer over SQLite, significantly reducing boilerplate code and ensuring query validation at compile time. Ideal for most typical Android application scenarios.
• SQLite directly: In older projects or when very low-level access and full control over schemas and queries were required. Requires more manual work.
• Realm: In several projects where performance was important for handling large volumes of data and complex objects. Realm is an object-oriented database, which is convenient when working with data models.
• Firebase Realtime Database / Cloud Firestore: For projects that require real-time data synchronization between devices and cloud storage. The choice between them depended on data structure and query needs. Realtime Database is well-suited for JSON tree data, while Cloud Firestore is suitable for document collections.

The choice of a specific database is determined by factors such as:

• Volume and type of data.
• Query complexity.
• Performance requirements.
• Data synchronization needs.
• Team expertise level.
• Availability of ready-made solutions and libraries.

For example, a typical implementation with Room includes:

// entity
@Entity(tableName = "users")
data class User(
    @PrimaryKey val id: Int,
    val name: String
)

// dao
@Dao
interface UserDao {
    @Query("SELECT * FROM users")
    fun getAll(): Flow<List<User>>

    @Insert(onConflict = OnConflictStrategy.IGNORE)
    suspend fun insert(user: User)
}

// database
@Database(entities = [User::class], version = 1)
abstract class AppDatabase : RoomDatabase() {
    abstract fun userDao(): UserDao
}