Relational databases are structured data management systems that organize information into interconnected tables, ensuring accuracy, consistency, and efficiency. They power transactions in finance, healthcare, and e-commerce industries by enforcing ACID compliance, optimizing queries with indexing, and using SQL for data retrieval. The primary components of relational databases include primary keys, foreign keys, and indexes, which work together to ensure data integrity and reliability. Relational databases are ideal for applications requiring precision, consistency, and scalability, such as finance, e-commerce, and healthcare sectors. They offer high-performance capabilities, multi-user environments, and complex queries, making them a gold standard for structured data management. However, they can struggle with large datasets, unstructured information, and high-speed transactions, emphasizing the need for optimization solutions like Acceldata's data observability platform to maintain system health at scale.