NoSQL: A new class of emerging databases (not only SQL)
- A non-relational database
- SQL syntax not supported
- The storage structure is completely different from the relational table in the traditional relational database, and the data stored in NoSQL is in kv form
- There is no universal language in the NoSQL world, and each NoSQL database has its own API and syntax, as well as a business scenario that excels
- There are quite a few types of products in NoSQL:
- Mongodb
- Redis
- Hbase Hadoop
- Cassandra Hadoop
Comparison of NoSQL and SQL databases:
- Different scenarios: SQL database is ideal for data query scenarios with particularly complex relationships, NoSQL instead
- Support for the transaction attribute: SQL supports transactions very well, and NoSQL basically does not support transactions
- The two continue to complement each other and present a trend of convergence
About Redis
- Redis is an open source API that is written in ANSI C, supports the web, can be persisted in memory, key-value databases, and provides multiple languages. From March 15, 2010 onwards, the development work of Redis is hosted by VMware. Since May 2013, the development of Redis has been sponsored by pivotal.
- Redis is a member of the NoSQL technology camp, which adapts various key-value data types to the storage needs of different scenarios, using a number of high-level interfaces that can be used to handle different roles, such as caching and queuing systems.
Redis Features
- Redis and other Key-value cache products have the following three features:
- Redis supports data persistence, which saves data in memory on disk and can be loaded again for use when restarting.
- Redis not only supports simple key-value types of data, but also provides storage of data structures such as List,set,zset,hash.
- Redis supports backup of data, that is, Master-slave mode of data backup.
- Redis Benefits
Redis Benefits
- The performance is very high –redis can read the speed is 110,000 times/s, the write speed is 81,000 times/s.
- Rich data types –redis support binary case Strings, Lists, hashes, sets and Ordered sets data type operations.
- All atomic –redis operations are atomic, and Redis supports atomic execution of several operations.
- Rich features –redis also supports publish/subscribe, notifications, key expiration, and more.
Redis Application Scenarios
- All the data used to do the cache (ehcache/memcached)--redis is in memory (in-memory database)
- Can be used to replace traditional databases in certain scenarios-such as social applications
- In some large systems, the ingenious implementation of some specific functions: Session sharing, Shopping cart
- As long as you have a rich imagination, redis can be used to give you infinite surprises ....
| Type |
Section represents |
Characteristics |
| Column Storage |
Hbase Cassandra Hypertable |
As the name implies, data is stored in columns. The biggest feature is the convenient storage of structured and semi-structured data, easy to do data compression, for a column or a few columns of the query has a very large IO advantage. |
Document storage |
Mongodb Couchdb |
Document storage is typically stored in a JSON-like format, and the stored content is document-based. This also gives you the opportunity to index certain fields and implement certain functions of the relational database. |
Key-value Storage |
Tokyo cabinet/tyrant Berkeley DB Memcachedb Redis |
You can quickly query to its value with key. In general, the format of the store regardless of the value of the full receipt. (Redis includes other features) |
Diagram Storage |
Neo4j Flockdb |
The best storage for graphical relationships. The use of traditional relational databases to address the performance of poor, and design use is not convenient. |
Object storage |
Db4o Versant |
The database is manipulated by object-oriented syntax, and data is accessed through objects. |
XML database |
Berkeley DB XML BaseX |
Efficiently stores XML data and supports internal query syntax for XML, such as Xquery,xpath. |
A brief introduction to the Redis database
