What level of complexity and database features were used in your projects?

In my projects, I used relational databases of medium and high complexity, such as PostgreSQL and MySQL. I mainly worked with normalized schemas, where data is divided into several tables with one-to-many and many-to-many relationships. To improve performance, I applied indexes on key fields and used transactions to ensure data integrity.

In some cases, I used NoSQL databases, such as MongoDB, for storing unstructured or semi-structured data, where schema flexibility and scalability are important. A feature of such projects was the need for fast reading and writing of large volumes of data, as well as horizontal scaling.

I also faced tasks related to query optimization, caching, and replication to ensure high availability and fault tolerance.