How can relational functional tables be created with RDB Store?

Read the original article：How can relational functional tables be created with RDB Store? Requirement Description When developing HarmonyOS applications, developers frequently require persistent data storage mechanisms that allow applications to retain state and manage user data across sessions. For lightweight storage of simple key-value pairs, Shared Preferences provides a convenient solution. However, when applications need to handle structured, complex, or relational data, developers often turn to RDB Store . Both technologies complement each other as local database services, enabling developers to select the most suitable option based on their use cases. Background Knowledge RDB Store is an SQL-based local database technology integrated into HarmonyOS. It provides developers with the ability to define schemas, create tables, and manage structured datasets with powerful querying capabilities. Unlike Shared Preferences, which is designed for simple data storage, RDB Store supports t