Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
Difference between Views and Materialized Views in SQL
The main constituent of any database is its tables, in order to make data accessibility custom there is concept of Views in other words we can say that with the help of Views of a table we can restrict any user to access only that data which is supposed to be accessed by him. Now on the basis of characteristic and features of the views we can distinguish between Views and Materialized Views.
In this article, we will discuss the important differences between Views and Materialized Views in SQL. But before, let’s have look into the basics of views and materialized view individually for better understanding of the differences between them.
Views in SQL
Views are the logical and virtual copy of a table that is created by executing a "SELECT query" statement. The views are not stored anywhere on the disk. Thus, every time, a query has to be executed when certain data is required. But, the query expression is stored on the disk.
Views do not have a storage/update cost associated with it. Views are designed with a specific architecture, which means there is an SQL standard to define a view. Views are used when data has to be accessed infrequently, but data gets updated frequently.
Materialized Views in SQL
Materialized views are the views whose contents are computed and stored. Materialized views are also a logical virtual table, but in this case the result of the query is stored in the table or the disk. The performance of the materialized views is better than normal views. This is because the data is stored on the disk.
Sometimes, materialized views are also called as "indexed views" because the table created after the query is indexed and can be accessed faster and efficiently. Materialized Views are used when data is to be accessed frequently and data in table not get updated on frequent basis.
Difference between Views and Materialized Views in SQL
The following table highlights the important differences between Views and Materialized Views −
| Key | Views | Materialized Views |
|---|---|---|
| Definition | Technically, the View of a table is a logical virtual copy of the table created by the "select query", but the result is not stored anywhere in the disk. Whenever we need the data, we need to fire the query. So, the user always gets the updated or latest data from the original tables. | Materialized views are also the logical virtual copy of data−driven by the "select query", but the result of the query will get stored in the table or disk. |
| Storage | In Views the resulting tuples of the query expression is not get storing on the disk only the query expression is stored on the disk. | In case of Materialized views both query expression and resulting tuples of the query get stored on the disk. |
| Query Execution | The query expression is stored on the disk and not its result, so the query expression gets executed every time when the user tries to fetch the data from it so that the user will get the latest updated value every time. | The result of the query gets stored on the disk and hence the query expression does not get executed every time when user try to fetch the data so that user will not get the latest updated value if it get changed in database. |
| Cost Effective | As Views does not have any storage cost associated with it so they also does not have any update cost associated with it. | Materialized Views have a storage cost associated with it so also have update cost associated with it. |
| Design | Views in SQL are designed with a fixed architecture approach due to which there is an SQL standard of defining a view. | Materialized Views in SQL are designed with a generic architecture approach, so there is no SQL standard for defining it, and its functionality is provided by some databases systems as an extension. |
| Usage | Views are generally used when data is to be accessed infrequently and data in table get updated on frequent basis. | Materialized Views are used when data is to be accessed frequently and data in table not get updated on frequent basis. |
Conclusion
Views and Materialized Views in SQL are quite different from each other. Views are used when data is to be accessed infrequently and the data in a table gets updated on a frequent basis. In contrast, Materialized Views are used when data is to be accessed frequently and data in table not get updated on frequent basis.
50K+ Views
