Databases are crucial for app development as they store and manage essential data, with relational databases, or SQL databases, being the most common type. Designing a relational database involves understanding its structure and the app's data needs, and Bubble, a no-code app development platform, simplifies this process by guiding users through creating a database. Relational databases excel in managing complex data relationships through tables that represent data types and fields, unlike spreadsheets that struggle with such complexity. For example, in an event planner app, Bubble facilitates the creation of necessary data types like User and Event, and fields such as Title, Location, and Organizer, while also linking related data types. This approach, combined with Bubble's user-friendly tools, allows non-programmers to design and develop databases and apps without needing extensive coding knowledge.