SQL (Structured Query Language) is primarily designed to work with relational databases, enabling the creation, manipulation, and retrieval of data stored in relational tables, making it best suited for relational databases. It provides a means of abstracting the logical data structures from the underlying physical data storage, thereby providing independence between the two. Additionally, SQL supports transactions that ensure ACID (Atomicity, Consistency, Isolation, Durability) properties, which are essential for maintaining data integrity.