At present, the three most commonly used data models are hierarchical model, grid model and relational model.

I. Hierarchy model

The hierarchical model organizes data into a one-to-many relational structure, and the hierarchical structure uses keywords to access each part of each level.

Hierarchical model developed earliest, with tree structure as its basic structure, and IMS model is its typical representative.

The advantages are convenient access and high speed; The structure is clear and easy to understand; Data modification and database expansion are easy to realize; It is very convenient to retrieve key attributes.

Second, the network model

Mesh model uses connection instructions or pointers to determine the explicit connection relationship between data, which is a many-to-many data organization mode.

Mesh data model represents the relationship between data through mesh structure, which developed earlier and has certain advantages. At present, it is still widely used, and the typical representative is DBTG model.

The advantage is that the complex relationship between data can be clearly and conveniently expressed.

Third, the relationship model.

The relational model organizes data in the form of record groups or data tables, so as to store and transform by using the relationships between various geographical entities and attributes. It is a very effective data organization method to establish the relationship between spatial data and attribute data.

Its advantages are flexible structure and simple concept, which can meet the query requirements of all Boolean logic operations and mathematical operation rules. Ability to search, combine and compare different types of data; It is very convenient to add and delete data.

Extended data:

According to different application levels, data models can be divided into three types: conceptual data model, logical data model and physical data model.

1. Conceptual data model is a user-oriented and objective world-oriented model, which is mainly used to describe the conceptual structure of the world. It is the initial stage of database designer's design.

2. Logical data model is a model oriented to database system and supported by a specific database management system.

3. Physical data model is a model of computer physical representation, which describes the organizational structure of data on storage media. It is not only related to the specific DBMS, but also related to the operating system and hardware.

References:

Data Model-Baidu Encyclopedia