Introducing a simple database Database tutorial (1)

Database

1 Definition

Database can be simply explained as: an efficient medium for storing and processing data (mainly divided into two types: disk and memory).

2 Classification

According to different database storage media, it can be divided into two categories, namely: relational database (SQL) and non-relational database (NoSQL, Not Only SQL).

3 Example

Relational database:

Large-scale: Oracle, DB2, etc.;

Medium-sized: SQL Server, MySQL, etc.;

Small: Access etc.

Non-relational databases:

Memcached, MongoDB and Redis, etc.

4 Difference

Relational database:

Safe, it saves data to the disk, and it is basically impossible to lose data;

It is a waste of space because it stores data in the form of a two-dimensional table.

Non-relational database:

The efficiency of storing data is relatively high;

is not particularly safe, and a sudden power outage will cause data loss.

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