Title: Compare relational and non-relational database structures.
Course: Database Design and Management (Oracle) (10052) > Section: Exploring Database Technologies

Comparison should include a description of the two main database types:

- Relational, in which data is arranged according to a schema that allows data to be displayed as tables with rows and columns. Data integrity is of particular concern in relational databases, and relational database management systems (RDBMS) use a number of constraints to ensure that the data contained in the tables is reliable and accurate.
- Non-relational, or NoSQL (not only SQL), which can be schema agnostic, allowing unstructured and semi-structured data to be stored and manipulated. NoSQL databases fall into one or more of the following categories:
  - Key-Value stores (e.g., Redis, DynamoDB)
  - Wide-Column stores (e.g., Cassandra, HBase)
  - Document stores (e.g., MongoDB, Couchbase)
  - Graph databases (e.g., Neo4j, Amazon Neptune)
  - Search engines (e.g., Elasticsearch, Apache Solr)