The document discusses SQL (Structured Query Language) and NoSQL (Not Only SQL) databases, highlighting their differences in data management, schema structure, and suitability for various applications. SQL is characterized by a predefined schema and is optimal for complex queries, while NoSQL offers flexibility with a dynamic schema and scalability for large datasets. It also compares examples of relational databases like MySQL and non-relational databases like MongoDB, concluding that the choice of database depends on the specific requirements of a project.