HarmonyOS分布式数据库深度应用

1. 分布式数据库架构解析

HarmonyOS分布式数据库（Distributed DataStore）是支撑跨设备数据同步的核心组件，它基于底层分布式软总线能力，为应用程序提供跨设备数据访问和同步功能。

1.1 整体架构设计

分布式数据库采用分层架构设计，从上至下包括：

• 数据访问层：提供标准的数据操作API，支持KV数据模型和关系型数据操作
• 同步引擎层：负责设备间数据同步，冲突解决策略管理
• 存储引擎层：本地数据存储和管理，支持多种存储后端
• 通信适配层：基于分布式软总线实现设备间安全通信

这种架构使得应用程序能够以统一的方式访问本地和远端设备数据，无需关心底层的网络通信和数据同步细节。

1.2 数据分布与同步机制

分布式数据库通过以下机制实现高效的数据分布和同步：

数据分片策略：根据设备能力和数据特性智能分片，关键数据多设备备份，非关键数据按需分布。

增量同步：仅同步发生变化的数据项，大幅减少网络传输量，采用操作转换（OT）算法解决并发冲突。

最终一致性保证：在网络分区恢复后自动达成数据一致性，支持自定义冲突解决策略。

2. 分布式数据库基础操作

2.1 数据库初始化与配置

首先需要在应用中初始化分布式数据库，并配置相关参数：

import relationalStore from '@ohos.data.relationalStore';
import distributedDeviceManager from '@ohos.distributedDeviceManager';

class DistributedDatabaseManager {
  private rdbStore: relationalStore.RdbStore | null = null;
  private context: Context | null = null;
  
  // 初始化数据库
  async initDatabase(context: Context): Promise<void> {
    this.context = context;
    
    const config: relationalStore.StoreConfig = {
      name: 'DistributedAppDB.db',
      securityLevel: relationalStore.SecurityLevel.S1
    };
    
    try {
      // 创建或打开本地数据库
      this.rdbStore = await relationalStore.getRdbStore(context, config);
      
      // 配置分布式同步参数
      await this.setupDistributedConfig();
      
      console.info('分布式数据库初始化成功');
    } catch (error) {
      console.error('数据库初始化失败:', error);
      throw error;
    }
  }
  
  // 配置分布式同步
  private async setupDistributedConfig(): Promise<void> {
    if (!this.rdbStore) return;
    
    const distributedConfig: relationalStore.DistributedConfig = {
      autoSync: true, // 启用自动同步
      encryption: true, // 启用数据加密
      syncMode: relationalStore.SyncMode.PUSH_PULL, // 推拉同步模式
      securityLevel: relationalStore.SecurityLevel.S2
    };
    
    await this.rdbStore.setDistributedTables(distributedConfig, [
      'UserPreferences', 
      'DocumentData', 
      'ApplicationState'
    ]);
  }
  
  // 创建数据表
  async createTables(): Promise<void> {
    if (!this.rdbStore) throw new Error('数据库未初始化');
    
    const userTableSql = `
      CREATE TABLE IF NOT EXISTS UserPreferences (
        id INTEGER PRIMARY KEY AUTOINCREMENT,
        key TEXT NOT NULL UNIQUE,
        value TEXT,
        device_id TEXT,
        timestamp INTEGER,
        is_synced INTEGER DEFAULT 0
      )`;
    
    const documentTableSql = `
      CREATE TABLE IF NOT EXISTS DocumentData (
        id INTEGER PRIMARY KEY AUTOINCREMENT,
        doc_id TEXT NOT NULL,
        title TEXT,
        content TEXT,
        last_modified INTEGER,
        version INTEGER DEFAULT 1,
        device_id TEXT,
        conflict_version INTEGER DEFAULT 0
      )`;
    
    await this.rdbStore.executeSql(userTableSql);
    await this.rdbStore.executeSql(documentTableSql);
    
    // 创建索引提升查询性能
    await this.rdbStore.executeSql(
      'CREATE INDEX IF NOT EXISTS idx_doc_id ON DocumentData(doc_id)');
    await this.rdbStore.executeSql(
      'CREATE INDEX IF NOT EXISTS idx_timestamp ON UserPreferences(timestamp)');
  }
}

2.2 基础数据操作

实现分布式环境下的CRUD操作，需特别处理同步状态和冲突检测：

class DistributedDataOperations {
  private rdbStore: relationalStore.RdbStore;
  
  constructor(rdbStore: relationalStore.RdbStore) {
    this.rdbStore = rdbStore;
  }
  
  // 插入数据并标记需要同步
  async insertData(table: string, data: ValuesBucket): Promise<number> {
    try {
      // 添加分布式元数据
      data.putString('device_id', this.getLocalDeviceId());
      data.putLong('timestamp', Date.now());
      data.putBoolean('is_synced', false);
      
      const rowId = await this.rdbStore.insert(table, data);
      console.info(`数据插入成功，行ID: ${rowId}`);
      
      // 触发数据同步
      await this.triggerSync();
      return rowId;
    } catch (error) {
      console.error(`插入数据到表 ${table} 失败:`, error);
      throw error;
    }
  }
  
  // 查询数据（支持跨设备查询）
  async queryData(
    table: string, 
    columns: string[], 
    predicates: relationalStore.RdbPredicates
  ): Promise<relationalStore.ResultSet> {
    try {
      const resultSet = await this.rdbStore.query(predicates, columns);
      console.info(`查询到 ${resultSet.rowCount} 条记录`);
      return resultSet;
    } catch (error) {
      console.error(`查询表 ${table} 失败:`, error);
      throw error;
    }
  }
  
  // 更新数据并处理版本冲突
  async updateDataWithConflictResolution(
    table: string,
    predicates: relationalStore.RdbPredicates,
    data: ValuesBucket
  ): Promise<boolean> {
    try {
      // 检查版本冲突
      const currentVersion = await this.getCurrentVersion(predicates);
      const newVersion = currentVersion + 1;
      
      data.putLong('version', newVersion);
      data.putBoolean('is_synced', false);
      
      const affectedRows = await this.rdbStore.update(data, predicates);
      
      if (affectedRows > 0) {
        await this.triggerSync();
        return true;
      }
      
      // 处理更新冲突
      return await this.handleUpdateConflict(table, predicates, data, currentVersion);
    } catch (error) {
      console.error('更新数据失败:', error);
      return false;
    }
  }
  
  // 获取本地设备ID
  private getLocalDeviceId(): string {
    // 实际实现中应从设备管理服务获取
    return 'local_device_001';
  }
  
  // 触发数据同步
  private async triggerSync(): Promise<void> {
    try {
      if (this.rdbStore.sync) {
        await this.rdbStore.sync({
          mode: relationalStore.SyncMode.PUSH,
          devices: [] // 空数组表示同步到所有可信设备
        });
      }
    } catch (error) {
      console.error('触发同步失败:', error);
    }
  }
}

3. 跨设备数据同步实战

3.1 同步策略配置

配置不同的同步策略以满足业务需求：

class SyncStrategyManager {
  private rdbStore: relationalStore.RdbStore;
  
  constructor(rdbStore: relationalStore.RdbStore) {
    this.rdbStore = rdbStore;
  }
  
  // 配置实时同步策略（用于重要数据）
  setupRealtimeSync(tables: string[]): void {
    tables.forEach(async (table) => {
      await this.rdbStore.setSyncConfig(table, {
        mode: relationalStore.SyncMode.PUSH_PULL,
        triggerCondition: relationalStore.TriggerCondition.ON_DATA_CHANGE,
        delay: 0, // 立即同步
        retryCount: 3,
        retryDelay: 1000
      });
    });
  }
  
  // 配置延迟同步策略（用于非关键数据）
  setupLazySync(tables: string[]): void {
    tables.forEach(async (table) => {
      await this.rdbStore.setSyncConfig(table, {
        mode: relationalStore.SyncMode.PUSH,
        triggerCondition: relationalStore.TriggerCondition.ON_APP_FOREGROUND,
        delay: 5000, // 5秒延迟
        retryCount: 1
      });
    });
  }
  
  // 手动触发同步
  async manualSync(devices: string[]): Promise<boolean> {
    try {
      const syncResult = await this.rdbStore.sync({
        mode: relationalStore.SyncMode.PUSH_PULL,
        devices: devices,
        timeout: 30000 // 30秒超时
      });
      
      console.info(`同步完成，成功设备: ${syncResult.successDevices}, 失败设备: ${syncResult.failDevices}`);
      return syncResult.failDevices.length === 0;
    } catch (error) {
      console.error('手动同步失败:', error);
      return false;
    }
  }
  
  // 订阅同步状态变化
  subscribeSyncStatus(): void {
    this.rdbStore.on('dataChange', (event: relationalStore.SyncEvent) => {
      switch (event.eventType) {
        case relationalStore.SyncEventType.SYNC_COMPLETE:
          this.handleSyncComplete(event);
          break;
        case relationalStore.SyncEventType.SYNC_FAIL:
          this.handleSyncFailure(event);
          break;
        case relationalStore.SyncEventType.DATA_PUSHED:
          this.handleDataPushed(event);
          break;
      }
    });
  }
  
  private handleSyncComplete(event: relationalStore.SyncEvent): void {
    console.info(`同步完成，设备: ${event.deviceId}, 表: ${event.table}`);
    // 更新本地同步状态
    this.markDataAsSynced(event.table, event.deviceId);
  }
  
  private handleSyncFailure(event: relationalStore.SyncEvent): void {
    console.error(`同步失败，设备: ${event.deviceId}, 错误: ${event.error}`);
    // 实现重试逻辑
    this.retrySync(event);
  }
}

3.2 冲突检测与解决

实现多设备并发修改时的冲突解决机制：

class ConflictResolutionManager {
  private rdbStore: relationalStore.RdbStore;
  
  constructor(rdbStore: relationalStore.RdbStore) {
    this.rdbStore = rdbStore;
  }
  
  // 检测并解决冲突
  async detectAndResolveConflicts(table: string): Promise<void> {
    const conflicts = await this.detectConflicts(table);
    
    for (const conflict of conflicts) {
      const resolution = await this.resolveConflict(conflict);
      await this.applyResolution(conflict, resolution);
    }
  }
  
  // 检测数据冲突
  private async detectConflicts(table: string): Promise<Conflict[]> {
    const conflicts: Conflict[] = [];
    
    // 查询存在版本冲突的记录
    const predicates = new relationalStore.RdbPredicates(table);
    predicates.greaterThan('conflict_version', 0);
    
    const resultSet = await this.rdbStore.query(predicates, [
      'id', 'doc_id', 'version', 'conflict_version', 'device_id'
    ]);
    
    while (resultSet.goToNextRow()) {
      conflicts.push({
        id: resultSet.getLong(resultSet.getColumnIndex('id')),
        docId: resultSet.getString(resultSet.getColumnIndex('doc_id')),
        version: resultSet.getLong(resultSet.getColumnIndex('version')),
        conflictVersion: resultSet.getLong(resultSet.getColumnIndex('conflict_version')),
        deviceId: resultSet.getString(resultSet.getColumnIndex('device_id'))
      });
    }
    
    resultSet.close();
    return conflicts;
  }
  
  // 解决冲突（支持多种策略）
  private async resolveConflict(conflict: Conflict): Promise<ConflictResolution> {
    // 基于时间戳的解决策略（最后写入获胜）
    if (this.useTimestampStrategy(conflict)) {
      return await this.timestampBasedResolution(conflict);
    }
    
    // 基于设备优先级的解决策略
    if (this.useDevicePriorityStrategy(conflict)) {
      return await this.devicePriorityBasedResolution(conflict);
    }
    
    // 自定义业务逻辑解决策略
    return await this.customBusinessResolution(conflict);
  }
  
  // 时间戳解决策略
  private async timestampBasedResolution(conflict: Conflict): Promise<ConflictResolution> {
    // 获取各设备的最新时间戳
    const timestamps = await this.getConflictTimestamps(conflict);
    const latestEntry = this.getLatestTimestampEntry(timestamps);
    
    return {
      winningVersion: latestEntry.version,
      resolutionType: 'TIMESTAMP_BASED',
      mergedData: latestEntry.data
    };
  }
  
  // 应用解决方案
  private async applyResolution(conflict: Conflict, resolution: ConflictResolution): Promise<void> {
    const predicates = new relationalStore.RdbPredicates('DocumentData');
    predicates.equalTo('id', conflict.id);
    
    const values: ValuesBucket = new ValuesBucket();
    values.putLong('version', resolution.winningVersion);
    values.putLong('conflict_version', 0); // 清除冲突标记
    values.putBoolean('is_synced', false);
    
    if (resolution.mergedData) {
      // 应用合并后的数据
      Object.keys(resolution.mergedData).forEach(key => {
        values.putObject(key, resolution.mergedData[key]);
      });
    }
    
    await this.rdbStore.update(values, predicates);
    console.info(`冲突解决完成，记录ID: ${conflict.id}`);
  }
}

4. 分布式数据查询优化

4.1 跨设备联合查询

实现高效的多设备数据查询和聚合：

class DistributedQueryEngine {
  private rdbStore: relationalStore.RdbStore;
  private deviceManager: distributedDeviceManager.DeviceManager;
  
  constructor(rdbStore: relationalStore.RdbStore) {
    this.rdbStore = rdbStore;
  }
  
  // 执行跨设备联合查询
  async executeDistributedQuery(
    query: DistributedQuery
  ): Promise<QueryResult> {
    const localResults = await this.executeLocalQuery(query);
    const remoteResults = await this.executeRemoteQueries(query);
    
    // 合并结果
    return this.mergeResults(localResults, remoteResults, query.mergeStrategy);
  }
  
  // 执行本地查询
  private async executeLocalQuery(query: DistributedQuery): Promise<any[]> {
    const predicates = this.buildPredicates(query);
    const resultSet = await this.rdbStore.query(predicates, query.columns);
    
    const results: any[] = [];
    while (resultSet.goToNextRow()) {
      results.push(this.extractRowData(resultSet, query.columns));
    }
    
    resultSet.close();
    return results;
  }
  
  // 执行远程设备查询
  private async executeRemoteQueries(query: DistributedQuery): Promise<RemoteResult[]> {
    const trustedDevices = await this.getTrustedDevices();
    const remoteResults: RemoteResult[] = [];
    
    // 并行查询所有可信设备
    const queryPromises = trustedDevices.map(device => 
      this.queryRemoteDevice(device, query)
    );
    
    const results = await Promise.allSettled(queryPromises);
    
    results.forEach((result, index) => {
      if (result.status === 'fulfilled') {
        remoteResults.push({
          deviceId: trustedDevices[index],
          data: result.value,
          timestamp: Date.now()
        });
      }
    });
    
    return remoteResults;
  }
  
  // 构建查询条件
  private buildPredicates(query: DistributedQuery): relationalStore.RdbPredicates {
    const predicates = new relationalStore.RdbPredicates(query.table);
    
    if (query.filters) {
      query.filters.forEach(filter => {
        switch (filter.operator) {
          case 'EQ':
            predicates.equalTo(filter.field, filter.value);
            break;
          case 'GT':
            predicates.greaterThan(filter.field, filter.value);
            break;
          case 'LT':
            predicates.lessThan(filter.field, filter.value);
            break;
        }
      });
    }
    
    if (query.orderBy) {
      predicates.orderBy(query.orderBy.field, query.orderBy.descending);
    }
    
    if (query.limit) {
      predicates.limit(query.limit);
    }
    
    return predicates;
  }
  
  // 合并本地和远程结果
  private mergeResults(
    localResults: any[], 
    remoteResults: RemoteResult[], 
    strategy: MergeStrategy
  ): QueryResult {
    switch (strategy) {
      case 'UNION_ALL':
        return this.unionAllMerge(localResults, remoteResults);
      case 'LATEST_FIRST':
        return this.latestFirstMerge(localResults, remoteResults);
      case 'DEVICE_PRIORITY':
        return this.devicePriorityMerge(localResults, remoteResults);
      default:
        return this.defaultMerge(localResults, remoteResults);
    }
  }
}

4.2 查询性能优化

实现查询缓存和索引优化：

class QueryOptimizationManager {
  private queryCache: Map<string, CacheEntry>;
  private maxCacheSize: number = 1000;
  
  constructor() {
    this.queryCache = new Map();
  }
  
  // 带缓存的查询
  async queryWithCache(
    predicates: relationalStore.RdbPredicates, 
    columns: string[]
  ): Promise<any[]> {
    const cacheKey = this.generateCacheKey(predicates, columns);
    
    // 检查缓存
    const cachedResult = this.getFromCache(cacheKey);
    if (cachedResult && !this.isCacheExpired(cachedResult)) {
      console.info('缓存命中');
      return cachedResult.data;
    }
    
    // 执行查询并缓存结果
    const result = await this.executeAndCacheQuery(predicates, columns, cacheKey);
    return result;
  }
  
  // 生成缓存键
  private generateCacheKey(predicates: relationalStore.RdbPredicates, columns: string[]): string {
    const predicateString = predicates.getWhereClause();
    const columnString = columns.sort().join(',');
    return `${predicateString}|${columnString}`;
  }
  
  // 执行查询并缓存
  private async executeAndCacheQuery(
    predicates: relationalStore.RdbPredicates,
    columns: string[],
    cacheKey: string
  ): Promise<any[]> {
    const startTime = Date.now();
    
    // 使用事务提升查询性能
    const result = await this.executeQueryInTransaction(predicates, columns);
    
    const queryTime = Date.now() - startTime;
    console.info(`查询执行时间: ${queryTime}ms`);
    
    // 缓存结果
    this.addToCache(cacheKey, result, queryTime);
    
    return result;
  }
  
  // 在事务中执行查询
  private async executeQueryInTransaction(
    predicates: relationalStore.RdbPredicates,
    columns: string[]
  ): Promise<any[]> {
    // 开始事务
    await this.rdbStore.beginTransaction();
    
    try {
      const resultSet = await this.rdbStore.query(predicates, columns);
      const results: any[] = [];
      
      while (resultSet.goToNextRow()) {
        results.push(this.extractRowData(resultSet, columns));
      }
      
      resultSet.close();
      await this.rdbStore.commit(); // 提交事务
      
      return results;
    } catch (error) {
      await this.rdbStore.rollback(); // 回滚事务
      throw error;
    }
  }
  
  // 清理过期缓存
  private cleanupExpiredCache(): void {
    const now = Date.now();
    for (const [key, entry] of this.queryCache.entries()) {
      if (now - entry.timestamp > this.cacheTTL) {
        this.queryCache.delete(key);
      }
    }
  }
}

5. 实战案例：分布式笔记应用

下面通过一个完整的分布式笔记应用案例，展示分布式数据库的实际应用。

5.1 数据模型设计

class DistributedNoteApp {
  private dbManager: DistributedDatabaseManager;
  private syncManager: SyncStrategyManager;
  private conflictManager: ConflictResolutionManager;
  
  // 初始化笔记应用
  async initialize(context: Context): Promise<void> {
    this.dbManager = new DistributedDatabaseManager();
    await this.dbManager.initDatabase(context);
    await this.dbManager.createTables();
    
    this.syncManager = new SyncStrategyManager(this.dbManager.getRdbStore());
    this.conflictManager = new ConflictResolutionManager(this.dbManager.getRdbStore());
    
    // 配置同步策略
    this.setupSyncStrategies();
    
    // 订阅数据变更事件
    this.subscribeToDataChanges();
  }
  
  // 创建新笔记
  async createNote(noteData: NoteData): Promise<string> {
    const noteId = this.generateNoteId();
    
    const values: ValuesBucket = new ValuesBucket();
    values.putString('note_id', noteId);
    values.putString('title', noteData.title);
    values.putString('content', noteData.content);
    values.putLong('created_time', Date.now());
    values.putLong('modified_time', Date.now());
    values.putLong('version', 1);
    values.putString('device_id', this.getLocalDeviceId());
    
    await this.dbManager.insertData('DocumentData', values);
    
    // 立即同步到其他设备
    await this.syncManager.manualSync([]);
    
    return noteId;
  }
  
  // 更新笔记内容
  async updateNote(noteId: string, newContent: string): Promise<boolean> {
    const predicates = new relationalStore.RdbPredicates('DocumentData');
    predicates.equalTo('note_id', noteId);
    
    const values: ValuesBucket = new ValuesBucket();
    values.putString('content', newContent);
    values.putLong('modified_time', Date.now());
    
    return await this.dbManager.updateDataWithConflictResolution(
      'DocumentData', predicates, values
    );
  }
  
  // 获取所有笔记（包括其他设备的笔记）
  async getAllNotes(): Promise<Note[]> {
    const query: DistributedQuery = {
      table: 'DocumentData',
      columns: ['note_id', 'title', 'content', 'modified_time', 'device_id'],
      filters: [],
      orderBy: { field: 'modified_time', descending: true },
      mergeStrategy: 'LATEST_FIRST'
    };
    
    const queryEngine = new DistributedQueryEngine(this.dbManager.getRdbStore());
    const results = await queryEngine.executeDistributedQuery(query);
    
    return this.transformToNotes(results);
  }
  
  // 处理笔记冲突
  async handleNoteConflicts(): Promise<void> {
    await this.conflictManager.detectAndResolveConflicts('DocumentData');
    
    // 重新同步解决冲突后的数据
    await this.syncManager.manualSync([]);
  }
}

5.2 高级同步特性

实现智能同步和离线支持：

class AdvancedSyncFeatures {
  private rdbStore: relationalStore.RdbStore;
  private isOnline: boolean = true;
  
  constructor(rdbStore: relationalStore.RdbStore) {
    this.rdbStore = rdbStore;
    this.monitorNetworkStatus();
  }
  
  // 监控网络状态
  private monitorNetworkStatus(): void {
    // 监听网络状态变化
    network.getDefaultNet().on('netAvailable', () => {
      this.isOnline = true;
      this.processPendingSyncs();
    });
    
    network.getDefaultNet().on('netLost', () => {
      this.isOnline = false;
    });
  }
  
  // 处理待同步队列
  private async processPendingSyncs(): Promise<void> {
    if (!this.isOnline) return;
    
    const pendingSyncs = await this.getPendingSyncs();
    for (const sync of pendingSyncs) {
      try {
        await this.executeSync(sync);
        await this.markSyncCompleted(sync.id);
      } catch (error) {
        console.error(`同步失败: ${sync.id}`, error);
        await this.recordSyncFailure(sync.id, error);
      }
    }
  }
  
  // 智能同步策略
  async intelligentSync(strategy: SyncStrategy): Promise<void> {
    const syncConfig = this.buildSyncConfig(strategy);
    
    switch (strategy.priority) {
      case 'HIGH':
        // 高优先级：立即同步，重试多次
        await this.immediateSync(syncConfig);
        break;
      case 'NORMAL':
        // 普通优先级：批量同步，适当延迟
        await this.batchSync(syncConfig);
        break;
      case 'LOW':
        // 低优先级：仅在WiFi环境下同步
        await this.wifiOnlySync(syncConfig);
        break;
    }
  }
  
  // 数据压缩传输
  private async compressDataForSync(data: any): Promise<Uint8Array> {
    const jsonString = JSON.stringify(data);
    const encoder = new TextEncoder();
    const encodedData = encoder.encode(jsonString);
    
    // 简单的压缩实现（实际应使用更高效的压缩算法）
    return this.simpleCompress(encodedData);
  }
  
  // 同步状态监控
  private setupSyncMonitoring(): void {
    this.rdbStore.on('syncProgress', (progress: SyncProgress) => {
      this.updateSyncUI(progress);
      
      if (progress.totalBytes > 1024 * 1024) { // 大于1MB
        this.showLargeSyncWarning(progress);
      }
    });
  }
}

6. 安全与性能优化

6.1 数据安全保护

class DataSecurityManager {
  private rdbStore: relationalStore.RdbStore;
  
  constructor(rdbStore: relationalStore.RdbStore) {
    this.rdbStore = rdbStore;
  }
  
  // 加密敏感数据
  async encryptSensitiveData(table: string, sensitiveFields: string[]): Promise<void> {
    const predicates = new relationalStore.RdbPredicates(table);
    const resultSet = await this.rdbStore.query(predicates, ['id', ...sensitiveFields]);
    
    while (resultSet.goToNextRow()) {
      const updateValues = new ValuesBucket();
      const id = resultSet.getLong(resultSet.getColumnIndex('id'));
      
      for (const field of sensitiveFields) {
        const plainText = resultSet.getString(resultSet.getColumnIndex(field));
        const encryptedText = await this.encrypt(plainText);
        updateValues.putString(field, encryptedText);
      }
      
      const updatePredicates = new relationalStore.RdbPredicates(table);
      updatePredicates.equalTo('id', id);
      
      await this.rdbStore.update(updateValues, updatePredicates);
    }
    
    resultSet.close();
  }
  
  // 设备访问控制
  setupDeviceAccessControl(): void {
    this.rdbStore.on('deviceAccessRequest', async (request: DeviceAccessRequest) => {
      const isTrusted = await this.verifyDeviceTrust(request.deviceId);
      const hasPermission = await this.checkDataAccessPermission(
        request.deviceId, request.table, request.operation
      );
      
      return isTrusted && hasPermission;
    });
  }
  
  // 数据访问审计
  async logDataAccess(
    deviceId: string, 
    table: string, 
    operation: string, 
    recordId: number
  ): Promise<void> {
    const auditValues: ValuesBucket = new ValuesBucket();
    auditValues.putString('device_id', deviceId);
    auditValues.putString('table_name', table);
    auditValues.putString('operation', operation);
    auditValues.putLong('record_id', recordId);
    auditValues.putLong('access_time', Date.now());
    
    await this.rdbStore.insert('DataAccessAudit', auditValues);
  }
}

总结

HarmonyOS分布式数据库通过精心的架构设计和优化策略，为开发者提供了强大的跨设备数据管理能力。关键技术和最佳实践包括：

核心架构优势：

• 统一的数据访问接口，简化跨设备数据操作
• 智能同步策略，平衡性能和数据一致性要求
• 灵活的冲突解决机制，支持多种业务场景

性能优化关键：

• 增量同步减少网络传输量
• 智能缓存提升查询性能
• 事务处理保证数据一致性

安全可靠性：

• 端到端数据加密保障隐私安全
• 设备认证和访问控制机制
• 完善的错误处理和恢复策略

通过本文的实战案例和代码示例，开发者可以快速掌握HarmonyOS分布式数据库的开发技巧，构建出高效可靠的跨设备应用。