Select the true statement about creating a view.
Options:
1) It is an all-in-one professional digital visual effects software application for Mac.
2) You can create a view by embedding a subquery within the CREATE VIEW statement.
3) View is type of interaction between double bar and data.
4) View is a programming language suitable for coders.
Answer (2)
The true statement about creating a view is Option 2: You can create a view by embedding a subquery within the CREATE VIEW statement.
Let's break down what a 'view' is and how it works in the context of databases:
What is a View in Databases?
A 'view' in database systems is a virtual table that is based on the result of a SELECT query. It is not a physical table but acts like one. A view can provide a way to simplify complex queries by encapsulating them into single objects that can be queried like tables.
How to Create a View?
You create a view using the CREATE VIEW statement, which includes a subquery that defines the view:
CREATE VIEW view_name AS SELECT column1, column2, ... FROM table WHERE condition;
The above SQL creates a new view named view_name that is defined by the SELECT query.
The subquery within the CREATE VIEW statement is used to determine which data is available through the view.
Benefits of Using Views:
Simplicity: Views can hide complex queries and present a simple interface for data access.
Security: Views can restrict access to sensitive data by only displaying certain columns or rows.
Consistency: They ensure consistent responses to the same query, making them useful for data integrity.
The incorrect statements:
Option 1 mentions a digital visual effects software for Mac, which is unrelated to database views.
Option 3 refers to an undefined interaction, not related to database concepts.
Option 4 incorrectly states that a view is a programming language, which it is not.
By understanding how to create and use views, you can effectively manage and present data in relational databases.
The correct answer is Option 2: You can create a view by embedding a subquery within the CREATE VIEW statement. A view acts as a virtual table in a database, allowing users to access simplified or controlled data. Creating a view is done through the SQL command CREATE VIEW , which includes a subquery.
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