Differences between simple and complex views in Oracle

A view is a logical table based on one or more tables or views. It does not contain data and allows you to query and modify the data in the table. A view-based table is called a base table, which is an Oracle database.
There are five types of objects: tables, views, sequences, indexes, and synonyms.

A view is a SELECT statement stored in the data dictionary. You can create a view to extract a logical set or combination of data.

Advantages of a view:

1. Access to the database because the view can selectively select a part of the database.

2. You can obtain results from complex queries through simple queries.

3. Maintain data independence and try to retrieve data from multiple tables.

4. Different views can be generated for the same data.

Views are classified into simple views and complex views:

1. A simple view only obtains data from a single table, while a complex view retrieves data from multiple tables;

2. A simple view does not contain functions and data groups, but contains complex views;

3. A simple view can implement DML operations, but not a complex view.

 

 

Note:

DML (data manipulation language): They are select, update, insert, and delete, just like their names. These four commands are used to operate the data in the database.
DDL (Data Definition Language): DDL is more than DML. The main Commands include create, alter, and drop. DDL is mainly used to define or change the table structure, data Types, links and constraints between tables, etc. They are mostly used when creating tables.