SQL Server Overview

Although the figure has been drawn out, I still don't quite understand what the view is. The concept in the courseware is a little abstract for me: The view is a table exported from one or more tables or views, its structure and data are based on the query of the table. Like a real table, a view also contains several defined data columns and multiple data rows. However, in essence, these data columns and data rows come from the referenced table. Therefore, a view is not a basic table that actually exists, but a virtual table. The data of the view is not stored in the database in the view structure, but in the table referenced by the view.

Later I checked Baidu encyclopedia, which was defined as follows: the view in the computer database is a virtual table whose content is defined by the query. Like a real table, a view contains a series of columns and row data with names. However, a view does not exist in the database as a stored dataset. Rows and columns are used to define tables referenced by View queries and dynamically generate tables when views are referenced. From the user's perspective, a view is to view data in the database from a specific perspective. Within the database system, a view is a virtual table defined by a query composed of select statements. From the perspective of the database system, the view is composed of data in one or more tables. From the perspective of the database system, the view is like a table, common operations that can be performed on a table can be applied to a view, such as query, insert, modify, or delete operations.

In comparison, it is easier to understand in the encyclopedia.