<p><strong>Relational Databases (SQL)</strong>:</p><ul><li><strong>Structure</strong>: Data is organized into tables (rows and columns).</li><li><strong>Schemas</strong>: Strong, predefined schema with rigid relationships (Foreign Keys).</li><li><strong>ACID Compliance</strong>: Ensures reliability in transactions (Atomicity, Consistency, Isolation, Durability).</li><li><strong>Examples</strong>: <strong>MySQL</strong>, <strong>PostgreSQL</strong>, <strong>SQLite</strong>.</li></ul><p><strong>NoSQL Databases</strong>:</p><ul><li><strong>Structure</strong>: Data is stored in various formats such as key-value pairs, documents, or graphs.</li><li><strong>Schemas</strong>: Flexible and dynamic schemas allow easy changes.</li><li><strong>Scalability</strong>: Horizontal scaling, making them ideal for handling large volumes of unstructured data.</li><li><strong>Examples</strong>: <strong>MongoDB</strong>, <strong>Cassandra</strong>, <strong>Redis</strong>.</li></ul>