The difference between views and materialized views in SQL

The main component of any database is its tables, and in the case of customization to make data accessible, there is the concept of views. In other words, through the table's view, we can restrict any user to only access the data he is supposed to access. Now based on the features and characteristics of views, we can differentiate 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 have no storage/update costs associated with them. Views are designed according to a specific schema, which means there is a SQL standard that defines views. Views are used when data needs to be accessed infrequently, but the data needs to be 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 "indexed views" because the table created after the query is indexed and can be accessed faster and more efficiently. Materialized views are used when the data needs to be accessed frequently and the data in the table is not updated frequently.

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, a view of a table is a logical virtual copy of the table created via a "select query", but the results are not stored on 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 (materialized views) are also logical virtual copies of the data, driven by "select queries", but the query results will be stored in tables or disks.
Storage	In Views the resulting tuples of the query expression is not get stored on the disk only the query expression is stored on the disk.	In the case of materialized views, both query expressions and tuples of query results are stored on disk.
Query execution	Query expressions are stored on disk rather than their results, so every time the user tries to extract data from it, the query expression is executed so that the user gets 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-effectiveness	Since Views have no storage cost associated with them, they also have no update cost associated with them.	Materialized Views have storage costs associated with them, and therefore also have update costs associated with them.
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 the data needs to be accessed frequently and the data in the table is not updated frequently.

in conclusion

In SQL, views (Views) and materialized views (Materialized Views) are very different. Views are used when the data is rarely accessed and the data in the table is frequently updated. On the contrary, use materialized views when the data needs to be accessed frequently and the data in the table is not updated frequently.

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