Redis Overview (i)

What is NoSQL?

NoSQL is the database solution to solve a series of problems, such as high concurrency, high availability, high scalability, and big data storage.

NOSQL, called a non-relational database, whose full name is not the only SQL. It can not replace the relational database, only as a good supplement to the relational database, etc.

categories of NoSQL

key value (key-value) store database
Related products: Tokyo cabinet/tyrant,Redis, Voldemort, Berkeley DB
Typical application: Content caching, primarily for high-access workloads that handle large amounts of data.
Data Model: A series of key-value pairs
Advantages: Quick Query
Disadvantage: stored data lacks structural
Column Store Database
Related products: Cassandra, HBase, Riak
Typical applications: Distributed File systems
Data Model: Store the same column of data together in a clustered type
Benefits: Fast Lookup, scalability, and distributed expansion
Disadvantage: The relative limitation of function
Document Type Database
Related products: CouchDB,MongoDB
Typical applications: Web applications (similar to Key-value, value is structured)
Data Model: A series of key-value pairs
Advantage: Data structure requirements are not strict
Disadvantage: Query performance is not high, and the lack of unified query syntax
Graph Database (graph)
Related databases: neo4j,infogrid, Infinite Graph
Typical applications: Social networks
Data Model: Graph structure
Advantage: Using graph structure correlation algorithm.
Disadvantage: The entire graph needs to be calculated to produce results, it is not easy to do a distributed cluster scheme.

What is Redis

Redis is a high-performance key-value database developed using the C language. Redis can store data through some key-value types.
Key value type:
String character type
Map Hash Type
List type
Set Collection type
SortedSet ordered collection types

application Scenarios for Redis

Caching (data queries, short connections, news content, product content, and so on). (Maximum use)
Session separation in a distributed cluster architecture.
Chat room's online friends list.
Task queue. (Seconds to kill, snapping, 12306, etc.)
Apply Leaderboards.
Website Access statistics.
Data expiration processing (can be accurate to milliseconds)