Database introduction, database

Database introduction, database

 

1. What is a database?

Database: Database, the medium for efficient data storage and processing (mainly two types of media: disk and memory ).

2. Database Classification

Based on different storage media, databases can be divided into two types: relational databases (SQL) and non-relational databases (NoSQL: Not Only SQL, Not relational databases are called non-relational databases)

3. What are the products in different database camps?

Relational Database Service

Large: Oracle, DB2

Medium: SQL-Server, My-SQL, etc.

Small: access, etc.

Non-relational databases: memcached, mongodb, and redis (synchronization technology.

4. Differences between the two database camps

Relational Database: Secure (it is basically impossible to lose data stored on a disk), easy to understand, and a waste of space (two-dimensional table Storage)

Non-relational databases: high efficiency, unsafe (power loss)