Siz qanday ma'lumotlar bazasini yaratgan bo'lar…

Men Room Persistence kutubxonasidan foydalanaman.

Bog'lamalarni qo'shish:

// build.gradle (ilova darajasida)
dependencies {
    def room_version = "2.5.2" // yoki joriy versiya

    implementation("androidx.room:room-runtime:$room_version")
    annotationProcessor("androidx.room:room-compiler:$room_version") // Kotlin uchun kapt("...") ni ishlating

    // Ixtiyoriy: Kotlin kengaytmalari va Coroutines uchun Room qo'llab-quvvatlash
    implementation("androidx.room:room-ktx:$room_version")
}

Entitilar (jadvalar)ni aniqlash:

@Entity bilan belgilangan sinf yarataman. Har bir maydon ustun bo'ladi va @PrimaryKey asosiy kalit bo'ladi.

// User.java
import androidx.room.Entity;
import androidx.room.PrimaryKey;

@Entity(tableName = "users")
public class User {
    @PrimaryKey(autoGenerate = true)
    public int id;

    public String firstName;
    public String lastName;
}

DAO (Ma'lumotlarga kirish obyekti)ni aniqlash:

@Dao bilan belgilangan interfeys yarataman, ma'lumotlarga kirish uchun metodlar bilan (kiritish, yangilash, o'chirish, so'rovlar).

// UserDao.java
import androidx.room.Dao;
import androidx.room.Delete;
import androidx.room.Insert;
import androidx.room.OnConflictStrategy;
import androidx.room.Query;
import androidx.room.Update;

import java.util.List;

@Dao
public interface UserDao {
    @Query("SELECT * FROM users")
    List<User> getAll();

    @Query("SELECT * FROM users WHERE id IN (:userIds)")
    List<User> loadAllByIds(int[] userIds);

    @Query("SELECT * FROM users WHERE first_name LIKE :first AND " +
           "last_name LIKE :last LIMIT 1")
    User findByName(String first, String last);

    @Insert(onConflict = OnConflictStrategy.IGNORE)
    void insertAll(User... users);

    @Delete
    void delete(User user);

    @Update
    void updateUsers(User... users);
}

Ma'lumotlar bazasini aniqlash:

RoomDatabase kengaytirilgan abstrakt sinf yarataman va @Database bilan belgilayman. Entitilar va DAO lar ro'yxatini o'z ichiga oladi.

// AppDatabase.java
import androidx.room.Database;
import androidx.room.RoomDatabase;

@Database(entities = {User.class}, version = 1)
public abstract class AppDatabase extends RoomDatabase {
    public abstract UserDao userDao();
}

Ma'lumotlar bazasini boshlash:

Ma'lumotlar bazasining nusxasini olaman, odatda Application sinfi yoki Activityda (lekin odatda Applicationda singleton uchun).

// Activity yoki Application sinfida
import android.content.Context;
import androidx.room.Room;

public class DatabaseInitializer {
    private static AppDatabase db;

    public static synchronized AppDatabase getDatabase(Context context) {
        if (db == null) {
            db = Room.databaseBuilder(context.getApplicationContext(),
                           AppDatabase.class, "database-name")
                    // .allowMainThreadQueries() // Tavsiya etilmaydi ishlab chiqarishda
                    // .fallbackToDestructiveMigration() // Migratsiyalar bilan ehtiyot bo'ling
                    .build();
        }
        return db;
    }
}

Ma'lumotlar bilan operatsiyalarni bajarish:

DAO nusxasini olgan holda, ma'lumotlar bazasida operatsiyalarni bajaraman, odatda fon ipida (masalan, AsyncTask, Executors, Coroutines, RxJava yordamida).

// Activity yoki boshqa joyda
new Thread(() -> {
   AppDatabase db = DatabaseInitializer.getDatabase(getApplicationContext());
   UserDao userDao = db.userDao();

   // Qo'shish
   User user1 = new User();
   user1.firstName = "John";
   user1.lastName = "Doe";
   userDao.insertAll(user1);

   // O'qish
   List<User> allUsers = userDao.getAll();
   // ... ma'lumotlarni ishlash
}).start();

Ushbu yondashuv SQLite ustidan abstraktsiya taqdim etadi, ma'lumotlar bazasini boshqarishni soddalashtiradi va konstruktor tekshiruvini ta'minlaydi.

Siz qanday ma'lumotlar bazasini yaratgan bo'lar edingiz?