update zh-cn/application-dev/database/database-preference-guidelines.md.

Signed-off-by: N@ge-yafang <geyafang@huawei.com>

zh-cn/application-dev/database/database-preference-guidelines.md

@@ -164,4 +164,6 @@
    ```
 ## 相关实例
 针对轻量级数据存储开发，有以下相关实例可供参考：
-- [`LiteStorage`：轻量级存储（eTS）（API7）](https://gitee.com/openharmony/app_samples/blob/master/data/LiteStorage)
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+- [`LiteStorage`：轻量级存储（eTS）（API7）](https://gitee.com/openharmony/app_samples/blob/master/data/LiteStorage)
+- [轻量级偏好数据库](https://gitee.com/openharmony/codelabs/tree/master/Data/Database)
+- [备忘录（eTS）](https://gitee.com/openharmony/codelabs/tree/master/Data/NotePad_OH_ETS)
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