MySQL series: View basic operations

1. Introduction to view 1.1 View definition

A view is a virtual table that is a table from one or more tables in a database.

Views can be defined on the basis of existing views.

Only the definition of the view is stored in the database, and the data in the view is not stored, and the data is stored in the original table.

The data in the view depends on the data in the original table, the data in the table changes, and the data that is displayed in the view changes.

1.2 View Effects

　　(1) Increased data security

With views, users can only query and modify the specified data.

The database Authorization command can restrict the user's operation permissions, but not to specific rows and columns. Use a view to restrict a user's permissions to specific rows and columns.

　　(2) Improve the logical independence of the table

Views can mask the impact of changes in the original table structure.

The original table structure adds columns and deletes unreferenced columns, without affecting the view.

MySQL series: View basic operations