Database comparison

Database comparison

2018-10-06 THUDM team Eunbi Choi

SQL vs NoSQL

1. High-level differences

   SQL	NoSQL
   Relational database	Non-relational database
   Table baesd	Document based, key-value pairs, graph databases or wide-column stores
   Scale vertically - Increase the load on a single server.	Scale horizontally - Scale across multiple hardwares.
   Pre-defined schema	Dynamic schema
   Structured and unchanging data	Unstructured and chainging data
   Language : SQL	Language : UnQL (syntax varies from database to database)
   Examples : MySql, Oracle, Sqlite, Postgres, MS-SQL	Examples : MongoDB, BigTable, Redis, Cassandra, CouchDB, Hbase
   ACID properties (Atomicity, Consistency, Isolation, Durability)	Brewer's CAP theorem (Consistency, Availability and Partition tolerance)
   Mature	Young
   Compelx queries	Simple low level queries

2. Advantage

   SQL	NoSQL
   Reliable data protection	Fast and high performance
   Privilege and password security system	Scalability
   Atomic transactions support	Larege volume data
   Execellent support with developed community	Fit for hierarchical data storage

3. When to use

   SQL	NoSQL
   Need to ensure ACID compliancy - For high transactional based applications.	Rapid development - Fit for agile development. Don't need to prepare data ahead of time.

MongoDB vs CouchDB

Redis

Redis is simple key-value in memory database with some data structures, therefore it can look up keys and return values very quickly.

According to the below article, Redis only needs 16MB to store one million key-value pairs. Expanding to 300 million keys, the total is just under 5GB.

Redis at Instagram (now switched to Cassandra from Redis): https://instagram-engineering.com/storing-hundreds-of-millions-of-simple-key-value-pairs-in-redis-1091ae80f74c

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Data to store

• room manager's data : id & password

• room info : room id, manager id, creation date -> memory

• blacklist : user id -> memory

• ...

The project's situation

• There is only one data (room manager's data) to store yet.

• Simple / small amount / changing data

• Inexpensive hardware

• Adopting agile methodology / Rapid development

• Famililar with SQL and Redis, unfamiliar with NoSQL

Decision: undecided

Deciding between MongoDB and Redis.

Reference

• SQL vs NoSQL

  https://www.thegeekstuff.com/2014/01/sql-vs-nosql-db/?utm_source=tuicool

• Mongodb vs Couchdb

  https://blog.scottlogic.com/2014/08/04/mongodb-vs-couchdb.html

  https://blog.panoply.io/couchdb-vs-mongodb

• When to use Redis

  http://oldblog.antirez.com/post/take-advantage-of-redis-adding-it-to-your-stack.html

  https://www.objectrocket.com/blog/how-to/top-5-redis-use-cases/

转载于:https://www.cnblogs.com/THUDM/p/9759699.html