Comparing View, Materialized View, and Aggregate Tables
Published by Sutha V
Sutha V, working as a CTO at Prowesstics.
Comparing View, Materialized View, and Aggregate Tables: Which is Best for Reporting?
The primary component of any database are its tables. To customize data accessibility, there is the concept of views, Views are used when data is rarely accessed and table data is frequently updated. In contrast, materialized views are used when data needs to be retrieved frequently and the table data is rarely updated. N tables must be connected in order for a business user to examine or generate their report and see the relevant data. This blog discusses the best option for a business user to utilize in their reporting tool—an aggregate table, a view, or a materialized view.
To better grasp the differences between views and materialized views, let's first take a closer look at their fundamentals. The key distinctions between views and materialized views are highlighted in the following table.
|
BASIC COMPARISON |
VIEW |
MATERIALIZED VIEW |
|
Basic |
Views are never stored, only displayed. |
Materialized View is stored on the disk. |
|
Define |
A view is a virtual table that is built from one or more base tables or views. |
A physical replica of the base table is the materialized view. |
|
Memory usage |
View doesn't need any memory. |
Materialized View makes use of memory. |
|
Speed |
Slow |
Fast |
|
Update |
View is updated, whenever the virtual table (View) is being used. |
The materialized view must be manually updated or updated with triggers. |
|
Syntax |
Create View V As |
Create Materialized View V Build [clause] Refresh [clause] On [Trigger] As |
|
Cost-effective |
Views don't have any storage costs, and as a result, they also don't have any update costs. |
Materialized views have both a storage cost and an update cost. |
|
Usage |
Views are used when data is hardly ever accessed and table data is frequently updated. |
Materialized views are used when data needs to be retrieved frequently and the table data is rarely updated. |
|
Design |
Views are built in accordance with the fixed design architectural method, which is based on the SQL standard describing a view. |
It cannot be defined by a predefined SQL standard; instead, the database offers the functionality as an extension. |
We can see from the above table that views and materialized views in SQL are very distinct from one another. Aggregate tables can also be used for reporting. Let's examine the reasons for using aggregate tables, views, and materialized views in reporting.
Aggregate Table for Reporting
Aggregation tables are summary tables that help you speed up processing for huge datasets in the DirectQuery storage option.
- We can perform scheduled loads on aggregated tables
- Data access is faster
- Unable to view real-time data
Loading data into aggregated tables can take longer depending on the number of tables we are combining, the complexity of the logic, and the volume of data in the tables.
Materialized View for reporting
Materialized views are typically faster for queries. Materialized views can greatly improve the performance of workloads characterized by common and repetitive queries.
- We can perform scheduled Refresh on materialized views
- Data access is faster
- Cant view the real-time data
Loading data in materialized views may take some time (like loading time for tables ) depending on the tables we are merging/complexing Logic/table data volume
View for reporting
Views come in handy when you want to display different angles on the same set of data. You can filter the columns in tables and choose particular inputs to display various data in the visual and tables when you view, create, or update a report.
- We can view the real-time data
- Based on the number of tables we are merging and table volume, accessing data may take longer than a materialized view.
Example Use Case:
We have a scenario to get the data from two tables with many case statements. End results will have 50 Columns and 4 rows.
View:
If this query is created as a view, view creation takes only seconds, but the select statement takes more than 4 minutes to execute.
Materialized View:
If this query is created as a materialized view, materialized view creation/refresh takes more than 5 minutes. The select statement takes seconds to execute.
Aggregation Table
If this query is created as an aggregate table, the table is loaded through an ETL in 2 minutes. The select statement takes seconds to execute.
Conclusion
In this blog, we have discussed the basic comparison and purpose of views, materialized views, and aggregate tables for reporting. Aggregate tables help you speed up processing for huge datasets. Materialized views respond faster compared to views. The view always provides up-to-date information and can help you view real-time data. You may see the main differences between these and make decisions based on your requirements.
