Ccs334 Big data analytics UNIT II ppt notes
- 1. UNIT II Jayapriya K N AP/CSE
- 2. NOSQL • NoSQL is a type of database management system (DBMS) that is designed to handle and store large volumes of unstructured and semi-structured data. Unlike traditional relational databases that use tables with pre-defined schemas to store data, NoSQL databases use flexible data models that can adapt to changes in data structures and are capable of scaling horizontally to handle growing amounts of data. • The term NoSQL originally referred to “non-SQL” or “non-relational” databases, but the term has since evolved to mean “not only SQL,” as NoSQL databases have expanded to include a wide range of different database architectures and data models.
- 3. Four main categories: • Document databases • Key-value stores • Column-family stores • Graph databases • NoSQL databases social media analytics, e- commerce, and gaming, content management systems, document management, and customer relationship management.
- 4. Continuation • A NoSQL database includes simplicity of design, simpler horizontal scaling to clusters of machines,has and finer control over availability. • NoSQL databases are designed to handle large amounts of unstructured or semi-structured data, and they can accommodate dynamic changes to the data model. • Many NoSQL stores compromise consistency in favor of availability, speed,, and partition tolerance.
- 5. Continuation • Most NoSQL stores lack true ACID(Atomicity, Consistency, Isolation, Durability) transactions but a few databases, such as MarkLogic, Aerospike, FairCom c-treeACE, Google Spanner, Symas LMDB, and OrientDB have made them central to their designs. • Most NoSQL databases offer a concept of eventual consistency in which database changes are propagated to all nodes so queries for data might not return updated data immediately or might result in reading data that is not accurate which is a problem known as stale reads.
- 6. Continuation • In document database ,each document can contain a different set of fields, making it easy to accommodate changing data requirements. Key Features of NoSQL: • Dynamic schema • Horizontal scalability • Document-based • Key-value-based:
- 7. Continuation • Column-based: • Distributed and high availability • Flexibility • Performance Advantages of NoSQL: • High scalability • Flexibility • High availability
- 8. Continuation • Scalability • Performance • Cost-effectiveness • Agility Disadvantages of NoSQL • Lack of standardization • Lack of ACID compliance • Narrow focus
- 9. Continuation • Open-source • Lack of support for complex queries • Lack of maturity • Management challenge • GUI is not available • Backup • Large document size
- 10. When should NoSQL be used: • When a huge amount of data needs to be stored and retrieved. • The relationship between the data you store is not that important • The data changes over time and is not structured. • Support of Constraints and Joins is not required at the database level • The data is growing continuously and you need to scale the database regularly to handle the data.
- 11. Aggregate Data Model in NoSQL • For the people who interact with data in databases, the Aggregate Data model will help in that interaction.