CodeGen

Overview

The MemberJunction CodeGen tool is a crucial component of the MemberJunction ecosystem. Its primary function is to streamline the process of reflecting database changes in the application layer, thereby enhancing the adaptability and maintainability of applications.

Functionality

1. Automatic Metadata Update: The CodeGen tool automatically detects changes made to your SQL Server database – such as adding new columns, creating new tables, or modifying field types. It then updates the metadata descriptions to reflect these changes.
2. Metadata Annotation: Users can annotate the metadata with additional information beyond what’s present in the SQL Server. This includes user-friendly names for tables and fields, descriptive text, and custom attributes like validation rules or high-level field types. This annotated metadata is retained even when CodeGen reruns and applies changes to the SQL Server database.
3. Subclass Generation: The tool auto-generates a subclass for each entity in your database. Each subclass represents the physical structure of the tables but routed through the metadata layer. This means that changes in the database schema automatically result in corresponding updates in these subclasses.
4. Custom Logic Integration: Developers can extend the autogenerated subclasses with their own second-level subclasses. This allows for the implementation of custom business logic, such as conditional validations, without affecting the autogenerated code.

Configuration: config.json File

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The config.json file is essential for configuring the CodeGen tool.

A typical configuration file for a tool like CodeGen might include:

• Database Connection Details: Information like database type, connection string, credentials, etc., for connecting to the SQL Server database.
• Metadata Parameters: Settings for how metadata should be handled, updated, and annotated.
• Output Settings: Configurations for where and how the autogenerated subclasses and other artifacts should be saved.
• Customization Options: Options to customize the generation process, like specifying naming conventions, excluding certain tables, or integrating custom logic templates.

Usage

1. Running CodeGen: To run the CodeGen tool, navigate to its directory and execute the appropriate command. This initiates the process of scanning the database and updating the metadata and subclasses as needed.
2. Modifying Generated Code: After running CodeGen, if you’d like to create your own sub-classes of any of the generated ones, you can do so. Just make sure that you use the RegisterClass decorator from @memberjunction/global and use a higher priority than the generated version for the given combination of Baseclass/Key. Doing this allows you to create custom functionality in your own sub-class of the generated sub-class without having to worry about your code being affected by future runs of CodeGen.
3. Integration into Development Workflow: Incorporate the running of CodeGen into your regular development workflow, especially after making database schema changes.

Conclusion

The MemberJunction CodeGen tool plays a pivotal role in maintaining the agility and robustness of applications built on the MemberJunction framework. By automating the synchronization between the database layer and application layer, it significantly reduces development overhead and improves the quality of the code. Understanding and effectively utilizing CodeGen is key to harnessing the full potential of the MemberJunction platform.