今天在适配家庭菜谱应用到HarmonyOS NEXT时，重点研究了HarmonyOS Design规范下的数据持久化方案。基于API12的@ohos.data.relationalStore关系型数据库模块，记录几个关键实现点：
1. 数据库建模
遵循HarmonyOS Design的"简洁高效"原则，设计了三张核心表：
typescript
// 数据库Schema定义
const SQL_CREATE_TABLE = `
CREATE TABLE IF NOT EXISTS recipe (
id INTEGER PRIMARY KEY AUTOINCREMENT,
name TEXT NOT NULL,
category TEXT CHECK(category IN ('中式','西式','日式')),
difficulty INTEGER DEFAULT 1
)
CREATE TABLE IF NOT EXISTS ingredient (
id INTEGER PRIMARY KEY,
recipe_id INTEGER,
name TEXT,
amount TEXT,
FOREIGN KEY (recipe_id) REFERENCES recipe(id) ON DELETE CASCADE
)`;
2. 数据库初始化
采用HarmonyOS推荐的异步事务处理：
typescript
import relationalStore from '@ohos.data.relationalStore';
let rdbStore: relationalStore.RdbStore;
const STORE_CONFIG = {
name: "RecipeDB.db",
securityLevel: relationalStore.SecurityLevel.S1
};
async function initDB() {
try {
rdbStore = await relationalStore.getRdbStore(this.context, STORE_CONFIG);
await rdbStore.executeSql(SQL_CREATE_TABLE);
console.info('Database initialized');
} catch (err) {
console.error(DB init failed: ${err.code}-${err.message});
}
}
3. 数据操作封装
为符合HarmonyOS Design的流畅体验要求，对CRUD操作做了线程优化：
typescript
// 插入菜谱示例
async function insertRecipe(recipe: Recipe) {
const valueBucket = {
"name": recipe.name,
"category": recipe.category,
"difficulty": recipe.difficulty
};
try {
await rdbStore.insert("recipe", valueBucket);
} catch (err) {
console.error(Insert failed: ${err.message});
}
}
// 查询带食材的完整菜谱
async function getFullRecipe(recipeId: number) {
const predicates = new relationalStore.RdbPredicates("recipe");
predicates.equalTo("id", recipeId);
const recipe = await rdbStore.query(predicates, ["id","name"]);
const ingPredicates = new relationalStore.RdbPredicates("ingredient");
ingPredicates.equalTo("recipe_id", recipeId);
const ingredients = await rdbStore.query(ingPredicates);
return { ...recipe, ingredients };
}
遇到的问题：
· 跨设备同步场景下需要结合DistributedDataKit扩展
· 大数据量分页查询时需注意Predicates的skip/limit设置
明天计划尝试用@ohos.data.preferences实现用户偏好存储，与主数据库配合使用。整个开发过程深刻感受到HarmonyOS Design在数据一致性方面的严谨要求。
