The simplest and most effective way to learn MySQL tutorial (i)

Database 1 Definitions

Database, can be simply interpreted as: efficient storage and processing of data media (mainly divided into two types of disk and memory).

2 classification

Depending on the database storage medium, it can be divided into two categories: relational database (SQL) and non-relational database (Nosql,not only SQL).

3 examples

Relational database:

• Large: Oracle, DB2, etc.;
• Medium: SQL Server, MySQL, etc.;
• Small: Access, and so on.

Non-relational database:

• Memcached, MongoDB, and Redis.

4 differences

Relational database:

• Security, which saves the data to the disk, the basic impossibility of the loss of data;
• Space is wasted because it stores data in a two-dimensional table.

Non-relational database:

• High efficiency of storing data;
• is not particularly secure, and sudden power outages can result in data loss.

--Reprinted from CSDN

The simplest and most effective way to learn MySQL tutorial (i)