Relational database is a database management system, which uses relational model to organize data. This paper will discuss the principle of relational database, including data storage strategy, referential integrity, logical relationship operation and user-defined query interface, so as to help readers better grasp these basic knowledge.

Understand the connotation of relationship

The relationship in relational database refers to the relationship between tables, which is a binary relationship. To understand the connotation of relationship, you can refer to the 123 paradigm to help you better grasp the principle of relational database.

Data storage strategy

The data storage strategy of relational database refers to how to store data on disk. It uses a table-based storage method to store data in tables, and each table corresponds to a file. This storage method can improve the efficiency of data access.

Referential integrity

Referential integrity in relational database requires referring to existing entities, and it is a constraint between two related tables, not a single relational description. A detailed explanation of reference integrity rules can help you better understand this concept.

Logical relationship operation priority

Logical relational operation is an operation in relational database, including union, intersection, difference, cartesian product and so on. In the logical relation operation, Y=(X+Y) belongs to the operation with higher priority.

Custom query interface

The relational database provides a user-defined query interface, and users can add query conditions as needed to make data query more flexible. This query method can improve query efficiency and user's work efficiency.