Database Systems

SQL vs NoSQL

SQL:
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They are relational database managment systems.
SQL data base uses structured query language for defining and managing data.
These have fixed, static or predefined schema.
Best suited for complex queries.
Vertically scalable (You can increase the load on a server by increasing the RAM, CPU, SSD).
Follow ACID property.
SQL data bases are tabale structure

NoSQL
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Non relational database management system.
They have dynamic schema.
Not good for complex queries.
Horizontally Scalable (You can inscerase adding more server into your database).
Follow cap(consistancy, availability, partition tolerence).
NoSQL database are document based, key value pair, graph databses or wide column spread.

Example databases:
SQL Data bases:
MySQL
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Open source, so it is free. owned by oracle. extremly establised database.compatible with many platform.

Oracle databases
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Managed by oracle, expensive, it has it's own dialect(PL/SQL).

Microsoft SQL database
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Onlyt work with linux and windows system, It has it's own sql dialect(T-SQL).

PostgreSQL
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Hybrid between SQL and NoSql databases.
Compatible with many platform.
Cost effective and it is open source database system.
it is an obejct oriented rlational database management system (ORDBMS) not simply RDBMS.


NoSQL Databases
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MogoDB
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Free to use.
High performance for simple queries.

Appache Cassandra
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Free open source, developed by facebook, and Apache took over on 2010.
fast read and write.
Poor for updating an deleting data.
popular for the IOT, excel for the log activity, error log, sensor data.

Google Cloud BigTable
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Not freely available,
Low latency, highly scalable, best of the machine leraning.

Appache Hbase
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Opren source and free. owned by Apache.
It specifically created to manage large databses.