I. Relational database ( SQL):
Mysql,Oracle
features : There is a relationship between data and data , between Tables and fields , between tables and tables
For example : Department table 001 section, Employee table 001
User table , user name , password
Classification Table and commodity tables , one -to-many relationships.
Advantages :There is a relationship between ① data, it is very convenient to make and delete data.
② relational databases have transactional operations. ensure the integrity of your data
Disadvantages :1, because of the relationship between data and data, the relationship is guaranteed by the underlying large number of algorithms
A lot of algorithms will slow down the system.
A large number of algorithms consume system resources
2, the huge amount of data additions and deletions will appear powerless .
It's probably down.
3, large Data Environment to maintain /expand the data Sheet , will become powerless
Update product Set cname = ' mobile phone digital ';// Modify all data
Put the Product table in the CNAME field, by varchar (100), Char
Ideal for handling general-scale data and safe .
two. Non-relational database ( NOSQL):
in order to deal with large amounts of data , the relationship between relational database needs to be removed.
the initial design of non-relational database is to replace of the relational database
Redis
Advantages :1, large amount of data deletion and modification, very easy to deal with
2, the maintenance of massive data is very easy .
Disadvantages :1. There is no relationship between data and data, so you cannot glance at it
2, non-relational database , no relationship , no strong transaction to ensure the integrity and security of data
Ideal for handling massive amounts of data and efficiency . Not necessarily safe .
Olympic Athletes Medal total
relational database + non-relational database = = = ="Project"
Important Data massive operational data, not important
Primary relational database (SQL) vs. non-relational database (NOSQL)