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What is the relational model structure of a database management system? This problem may be our daily study or work often see. I hope you learned something from this question. The following is the reference content brought to you by Xiaobian. Let's take a look together!

Relational database management system manages relations are several two-dimensional tables. Because in relational database, a table is a relationship, the relationship managed by relational database management system is multiple two-dimensional tables.

Relational database is a database based on relational database model, which processes the data in database by means of concepts and methods such as set algebra. It is also a set of tables organized into formal descriptions. The essence of this form of table is to load special collections of data items. The data in these tables can be accessed or reassembled in many different ways without reorganizing database tables. (Recommended learning: MySQL video tutorial)

The definition of a relational database creates a table of metadata or formal descriptions of tables, columns, ranges, and constraints.

Each table (sometimes referred to as a relationship) contains one or more data categories represented by columns. Each row contains a unique entity of data that is the category defined by the column. When creating a relational database, you can define ranges of possible values for data columns and further constraints that may be applied to that data value.

SQL is the standard user and application interface to relational databases. The advantage is that it is easy to expand, and after the initial database creation, a new data type can be added without modifying all existing applications. The mainstream relational databases include oracle, db2, sqlserver, sybase, mysql, etc.

relational model structure

1. Single data structure-relationship (table file). Relational database tables use two-dimensional tables to store data, which are logical groups of related information arranged in rows and columns, similar to Exkle worksheets. A database can contain any number of tables.

From the user's perspective, the logical structure of a relational model is a two-dimensional table consisting of rows and columns. This two-dimensional table is called a relationship. In layman's terms, a relationship corresponds to a table.

2. Tuples (records). A row in a table is a tuple, or record.

3. Attributes (fields). Each column in a data table is called a field. The table is defined by the various fields it contains. Each field describes the meaning of the data it contains. The design of the data table is actually the design of the field. When you create a data table, assign a data type to each field, defining their data length and other attributes. Fields can contain a variety of characters, numbers, and even graphics. Such as error! Reference source not found.

4. Attribute value. The intersection of rows and columns represents an attribute value, such as Database Principles, which is the attribute value of the course name

5, the main code. A primary key (also known as a primary key or key) is the data used to uniquely identify a tuple in a table. Keyword is used to ensure the uniqueness of records in a table. It can be a field or multiple fields. It is often used as an index field of a table. Each record has a different keyword, which uniquely identifies a record. Keywords are also called primary keys, or primary keys for short. Such as error! Reference source not found.

6. Domain. The range of values for the property.

7. Relationship model. A description of a relationship is called a relational schema. A description of a relationship, generally expressed as: relationship name (attribute 1, attribute 2... attribute n). For example, the above relationship can be described as: course (course number, course name, credit, teacher).

But the simple data structure of relational model can express rich semantics, describing entities and relationships between entities in the real world.

Thank you for reading! After reading the above, do you have a general understanding of the relational model structure of database management systems? I hope the content of this article is helpful to everyone. If you want to know more about related articles, please pay attention to the industry information channel.

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