Download to read offline
No SQL databases basics module 1 vtu notes
- 1.
- 2. Why NOSQL Aggregate DataModels More Details on Data Models
- 3. WHY NOSQL NoSQL databaseprovides much more flexibility when it comes to handling data. There is no requirement to specify the schema to start working with the application. Also, the NoSQL database doesn't put a restriction on the types of data you can store together. It allows you to add more new types as your needs change
- 4. THE VALUE OFRELATIONAL DATABASES Getting at Persistent Data Concurrency Integration A (Mostly) Standard Model
- 5. GETTING AT PERSISTENTDATA Need to Store Large Data. Two Ways storing Data Main Memory – Limited in Space – loss of Data due to power failures Backing Data - Large in Size – Slower Productivity Apps – Word Processor – File System Enterprise Applications – Database
- 6. CONCURRENCY Multiple UsersAccessing at a Time Majorly Modifying Data Transaction Handling Transactions should be Rolled Back if Needed Hotel Room Booking
- 7. INTEGRATION Applications Writtenby Multiple Teams Collaboration Shared Database Integration Concurrency Control of Database handles Multiple Applications
- 8. A (MOSTLY) STANDARDMODEL Relational databases have succeeded because they provide the core benefits we outlined earlier in a (mostly) standard way Vendors Might Differ but not the Benfits
- 9. IMPEDANCE MISMATCH Though RDBMSprovides many advantages still it is not perfect. One of the dissatisfaction for developers is “Impedance Mismatch” Impedance Mismatch The difference between the relational model and the in-memory data structures
- 10. IMPEDANCE MISMATCH Therelational data model organizes data into a structure of tables and rows, or more properly, relations and tuples The values in a relational tuple have to be simple—they cannot contain any structure, such as a nested record or a list if you want to use a richer inmemory data structure, you have to translate it to a relational representation to store it on disk
- 11.
- 12. IMPEDANCE MISMATCH TheSolution in earl 2000’s is OOP and OOD. OOD given solution to Impedance Mismatch Major issue is Integration with RDBMS Frame Works for Integrations like HIBERNATE Solution is not Feasible
- 13. APPLICATION AND INTEGRATION DATABASES Integration Database with multiple applications, usually developed by separate teams, storing their data in a common database. This improves communication because all the applications are operating on a consistent set of persistent data Complexity has been Increased Number of Applications is a Tedious Task In 2000’s the Paradigm Shift is “WEB SERVICES”
- 14. APPLICATION AND INTEGRATION DATABASES HTTP Flexibility in Exchanging the Data through HTTP REQ/RESP XML or JSON Application Specific Database instead of Integrated Database
- 15. ATTACK OF THECLUSTERS Growth in Millenium in the Name of Applications and Databases Y2K Problem Traffic on Websites Increased Social Media Log Data Mapping of Data To handle this kind of increase, you have two choices: up or out SCALE UP or GO OUT OF THE MARKET
- 16. ATTACK OF THECLUSTERS Scaling up implies bigger machines, more processors, disk storage, and memory. But bigger machines get more and more expensive, not to mention that there are real limits as your size increases. The alternative is to use lots of small machines in a cluster. A cluster of small machines can use commodity hardware and ends up being cheaper at these kinds of scales. It can also be more resilient— while individual machine failures are common, the overall cluster can be built to keep going despite such failures, providing high reliability.
- 17. ATTACK OF THECLUSTERS Relational databases are not designed to be run on clusters Clustered relational databases, such as the Oracle RAC or Microsoft SQL Server, work on the concept of a shared disk subsystem This mismatch between relational databases and clusters led some organization to consider an alternative route to data storage. Two companies in particular—Google and Amazon BigTable from Google and Dynamo from Amazon.
- 18. THE EMERGENCE OFNOSQL Late 90’s Open Source Carlo Strozzi This database stores its tables as ASCII files, each tuple represented by a line with fields separated by tabs The name comes from the fact that the database doesn’t use SQL as a query language The database is manipulated through shell scripts that can be combined into the usual UNIX pipelines
- 19. THE EMERGENCE OFNOSQL Relational databases use ACID transactions to handle consistency across the whole database. NoSQL databases offer a range of options for consistency and distribution Graph databases are one style of NoSQL databases that uses a distribution model similar to relational databases but offers a different data model that makes it better at handling data with complex relationships. NoSQL databases operate without a schema Useful when dealing with nonuniform data
- 20. KEY POINTS Relationaldatabases have been a successful technology for twenty years, providing persistence, concurrency control, and an integration mechanism. Application developers have been frustrated with the impedance mismatch between the relational model and the in-memory data structures. There is a movement away from using databases as integration points towards encapsulating databases within applications and integrating through services. The vital factor for a change in data storage was the need to support large volumes of data by running on clusters. Relational databases are not designed to run efficiently on clusters. NoSQL is an accidental neologism. There is no prescriptive definition—all you can make is an observation of common characteristics.
- 21. KEY POINTS Thecommon characteristics of NoSQL databases are Not using the relational model Running well on clusters Open-source Built for the 21st century web estates Schemaless The most important result of the rise of NoSQL is Polyglot Persistence – Various Data Storage options are available
- 22. AGGREGATE DATA MODELS A data model is the model through which we perceive and manipulate our data Data Model describes how we interact with the data in the database Distinct from a storage model, which describes how the database stores and manipulates the data internally Developer might point to an entity-relationship diagram of their database and refer to that as their data model containing customers, orders, products, and the like
- 23. AGGREGATE DATA MODELS Relational Model Consists of Rows and Columns in the form of Tables NoSQL solution has a different model that it uses, which we put into four categories widely used in the NoSQL ecosystem: Key-Value Document Column-Family Graph
- 24. AGGREGATES Relational modeltakes the information that we want to store and divides it into tuples (rows) A tuple is a limited data structure Cannot nest one tuple within another to get nested records, nor can you put a list of values or tuples within another. aggregate is a collection of related objects that we wish to treat as a unit