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Today, the editor brings you an article that introduces the data model of Mysql database. The editor thinks it is very practical, so I will share it for you as a reference. Let's follow the editor and have a look.

Hierarchical model

Hierarchical model is the earliest model used in database system, and its data structure is a "directed tree". The root node is at the top, the level is the highest, and the child nodes are arranged layer by layer. The characteristics of the hierarchical model are:

1. There is and only one root node

2. Other nodes have one or only one parent node.

Reticular model

The mesh model uses a mesh structure to represent the relationship between entities. Each node in the network represents a record type, and the connection is realized by a link pointer. The mesh model can not only represent the relationship of multiple subordinate relationships, but also the cross relationship between data, that is, the horizontal and vertical relationship between data. it is an extension of the hierarchical model. The mesh model can easily represent various types of relationships, but the structure is complex and the algorithm is difficult to standardize. It is characterized by:

1. Nodes are allowed to have more than one parent node

2. There can be more than one node without a parent.

Relation model

The relational model uses a two-dimensional table structure to represent the relationship between entities, which is based on the theory of relational mathematics. The data structure of the relational model is a collection of "two-dimensional table frameworks". Each two-dimensional table can also be called a relationship. In the relational model, the objects and results of operations are two-dimensional tables. Relational model is the most popular database model at present. The database management system that supports relational model is called relational database management system, and Access is a kind of relational database management system.

Characteristics:

1. The consistency of description, describing not only the entity itself, but also the relationship between entities.

2. Many-to-many connections can be expressed directly.

3. The relationship must be standardized, that is, each attribute is an inseparable data item, and tables are not allowed in the table.

4. The relational model is based on mathematical concepts and has a strong theoretical basis.

After reading the above, do you have a general understanding of the data model of the Mysql database? If you want to know more about the content of the article, welcome to follow the industry information channel, thank you for reading!

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