Which Statement Is True About the View Created With the Following Command?
A view in a database is a virtual table that is based on the result of a query. It is a saved query that can be used like a table to retrieve data. Views provide a way to simplify complex queries and can be used to restrict access to certain data. When creating a view, it is important to understand the implications of the command used and the resulting view. In this article, we will discuss the statement that is true about the view created with a specific command.
The command in question is:
CREATE VIEW my_view AS SELECT * FROM my_table WHERE condition;
This command creates a view named “my_view” by selecting all columns from “my_table” where a specified condition is met. The resulting view will only contain the rows that satisfy the given condition.
The statement that is true about the view created with this command is:
The view will display a subset of the rows from “my_table” based on the specified condition.
Q: Can I modify the data in a view created with this command?
A: It depends. In most cases, you cannot modify the data directly in a view. However, if the view is created using the WITH CHECK OPTION clause, you may be able to modify the data that satisfies the condition specified in the view’s query.
Q: Will the view reflect changes made to the underlying table?
A: Yes. When you query the view, it dynamically retrieves data from the underlying table. Any changes made to the table will be reflected in the view.
Q: Can I create an index on a view?
A: No. In most database systems, indexes cannot be created directly on views. However, you can create indexes on the underlying tables to improve the performance of queries executed on the view.
Q: Can I grant or revoke permissions on the view?
A: Yes. You can grant or revoke permissions on the view, just like you would with a table. This allows you to control access to the view and restrict certain users from retrieving data.
Q: Can I join multiple views together?
A: Yes. Views can be joined together in a query, just like tables. This can be useful when you want to combine data from multiple views into a single result set.
In conclusion, the statement that is true about the view created with the given command is that it will display a subset of the rows from the specified table based on the provided condition. Views are powerful tools in database management systems that allow for simplified and restricted access to data. Understanding the implications of the command used to create a view is essential for utilizing them effectively.