What are the most common techniques for documenting database schema?

Importante estabelecer o padr?o da nota??o para o modelo facilitando a interpreta??o. Existem diversas nota??es como as de Peter Chen, James Martin, Heuser, entre outros e cada um traz características diferentes para descrever entidades, relacionamentos e atributos.

What: Visual representations illustrating the relationships between different entities in the database. Why: Offers a clear and concise overview of the database structure.

In my experience with SQL databases, mostly SQLite, I found data dictionaries a bit overwhelming as most of the information can be found in the definition of each table. If you need to generate one, it's fairly easy to make a Python script to do so. In my opinion a good naming convention is often enough to describe each column of your table. If your database is generated on the flow, adding comments in the script that generates it could be enough as documentation. In my case, it was often enough to create a wiki to clearly explain the motivation and goal of each tables but not to describe each column separately.

What: Comprehensive repositories that define and describe data elements within a database. Why: Acts as a centralized source for metadata, ensuring consistency in understanding and usage.

What: Specialized languages (e.g., SQL Data Definition Language) used to define and structure database schemas. Why: Provides a formal and executable way to specify the database structure.

What: Inline comments within the database scripts or code, explaining specific sections or decisions. Why: Offers insights for developers maintaining or modifying the database, promoting understanding.

In my experience, having documentation close to code, is the best way to ensure that documentation gets updated (and improved). Of course, you should not document all of your queries, as some could be self-explanatory, or one can use some tools (such as ai prompt) to get an explanation. However, you should document any "hacks" or tricks that you used. If it took you several minutes to create a query, maybe this query is a good candidate for documentation.

What: Tools that automatically generate documentation from database metadata or code. Why: Saves time and ensures documentation stays up-to-date with the actual database structure.

Tools that generate documentation are a good way to keep your wiki up-to-date. If using them, it would be even better to have them running automatically (triggered by change or periodically). In my experience company guidelines is even better than some automatic documentation, having code and/or a structure that is self-explanatory is the best form of documentation.

1. Narrative Documentation: Include written documentation that provides a narrative overview of the database design, its purpose, and any conventions followed. 2. Change Logs: Document changes made to the database over time, including modifications to schema, tables, or data. 3. Security Considerations: Document access controls, encryption methods, and other security-related aspects to ensure a comprehensive understanding. 4. Usage Guidelines: Provide guidelines for developers and users on how to interact with and query the database effectively.

Some other points that could be added: 1. Naming Convention 2. Guidelines and best practices 3. Database architecture review (similar as a code review) In my experience, ensure that your documentation can be easily updated (otherwise you have a risk that your developers will not update it) and is easy to use. Ensure that the naming of your tables/columns is understandable. Early-stage architecture/design review will also improve scalability and maintainability.