Overview

Backend development includes three categories of development: model, logic, and process. Figure 1 describes the functions of each category.

Figure 1 Backend development
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Model development: In Huawei Cloud Astro Zero, services are built on models. Therefore, you need to define a data model for an application. This means identifying how service data is to be stored, essentially setting up a database and creating tables within it. In Huawei Cloud Astro Zero, these tables are objects. For example, when developing a warehouse commodity management application, you need to create two objects: "commodity" and "warehouse". The "commodity" object would hold information like the item code, status, total inventory, current stock, and the relationship with the warehouse. Similarly, the "warehouse" object would contain details such as the warehouse name, code, address, and a record ID. To query associated data between multiple objects, you can create an object view.

Logic development: After data models are developed, the next step is to develop the logic that will drive the services. This involves creating service APIs and the underlying logic that processes data. In Astro Zero, this is done using either scripts or flows. Scripts are written in code and are ideal for complex service logic, while flows offer a graphical interface that is ideal for simpler scenarios, with a recommendation to keep it within 20 diagram elements for clarity. Triggers intuitively display service processes to users. Once set up, triggers automate operations without the need for manual execution by users. For example, if you have a script that has already done its job and you want to add a new function without altering the script, you can set up a trigger. This makes it easy to expand functionality without changing the existing logic, keeping operations smooth and efficient.

Process development: Business Progress Management (BPM) is a visual tool that works alongside flows to manage service processes that involve user behaviors, such as approvals and ticket handling. While flows handle the system's detailed logical steps, BPM brings in the user by connecting these flows to tasks on specific pages, making the interaction between humans and the system smooth. Also, for automated service processes, you can set up scheduled tasks. An example would be scheduling a task that automatically deactivates expired products at 3:00 AM daily.

**Table 1** Backend development
Category	Feature	Feature Description
Model development	Objects	An object is similar to a table in a database of a traditional service system. Each object corresponds to a database table for storing the configuration data and service data required by a service system.
	Events	An event in a business process marks a significant change. Once an event is defined, you can send it out, receive it, and then analyze and handle the data associated with that event.
	Structures	A structure is a defined data format that restricts the use of input, output, and internal variables during application development. In Huawei Cloud Astro Zero, structures can be used for external inputs, output parameters, and variable structures in flows, connectors, and BPMs.
Logic development	Scripts	Similar to flows, scripts are used to develop service APIs and logic. Astro allows you to develop TypeScript scripts for complex service logic.
	Flows	Similar to scripts, flows are used to develop service APIs and logic. Flows are graphical and ideal for simpler scenarios, with a recommendation to keep it within 20 diagram elements for clarity.
	Triggers	Triggers intuitively display service processes to users. Once set up, triggers automate operations without the need for manual execution by users.
Process development	Overview	Similar to flows, BPM is also a visual tool. However, it focuses on the service processes that involve user behaviors, such as approvals and ticket handling.
Process development	Scheduled Tasks	You can create a scheduled task to automatically execute a script or a flow for specific service functions. For example, a scheduled task in the system suspends expired offerings at 03:00 every day.