What are the main models of the database? What are the characteristics of these models?

Two types of data models: data models are divided into two categories (belonging to two different levels, and different models are used when developing and using databases).

Conceptual model, also known as information model, is used to model data and information for database design from the perspective of users.

Logical model and physical model. Logical model mainly includes grid model, hierarchical model, relational model and object-oriented model. It models data from the perspective of computer system and is used for the implementation of DBMS.

Physical model is the lowest abstraction of data, which describes how data is represented and accessed in the system, as well as how it is stored and accessed on disk or tape.

Conceptual model: the basic concept of the information world.

Usage: the language of communication between database designers and users. But take the E-R diagram!

The most commonly used data models: non-relational model, hierarchical model and grid model; Relational model; Object-oriented model, object-relational model.