Relational database
A relational database organizes information into tables and lets those tables be connected, or related, to one another.
For example, a business application might store customers in one table, orders in another, and invoices in a third. Each order can be linked to the customer who placed it, and each invoice can be linked to the order it belongs to. The database can then answer questions that involve information from more than one table, such as “Which customers placed orders last month but still have unpaid invoices?”
This structure is often a natural fit for business software because business data tends to contain many relationships. Relational databases also make it possible to enforce rules that keep data consistent—for example, preventing an order from referring to a customer who does not exist.
PostgreSQL, MySQL, and Microsoft SQL Server are common relational database systems.
When is a relational database useful?
Relational databases are especially useful when:
- information has clear relationships;
- data consistency is important;
- an application needs flexible reporting or queries; or
- the questions people will ask of the data may change over time.
They are not automatically the best choice for every application. Other database designs may be simpler or perform better for highly specialized data or very large workloads. The right choice depends on the structure of the data and how the application needs to use it.
If your business already runs on Microsoft Access, a spreadsheet, or a no-code tool like Airtable, you may not need a relational database at all. Those tools can cover a lot of the same ground without requiring specialized skills. Relational databases become worth the investment as your data and reporting needs grow past what those tools handle comfortably.