Virtual Table Access Control in Databases | Exam Answer

Virtual Table Access Control

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What would be the name of a Logical or Virtual Table dynamically generated to restrict the information a user can access in a database?

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A. B. C. D.

The Answer: Database views; Database views are mechanisms that restrict access to the information that a user can access in a database.Source: KRUTZ,

Ronald L.

& VINES, Russel.

D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 35

Wikipedia has a detailed explantion as well: In database theory, a view is a virtual or logical table composed of the result set of a query.

Unlike ordinary tables (base tables) in a relational database, a view is not part of the physical schema: it is a dynamic, virtual table computed or collated from data in the database.

Changing the data in a table alters the data shown in the view.

Views can provide advantages over tables; They can subset the data contained in a table They can join and simplify multiple tables into a single virtual table Views can act as aggregated tables, where aggregated data (sum, average etc.) are calculated and presented as part of the data Views can hide the complexity of data, for example a view could appear as Sales2000 or Sales2001, transparently partitioning the actual underlying table Views do not incur any extra storage overhead Depending on the SQL engine used, views can provide extra security.

Limit the exposure to which a table or tables are exposed to outer world Just like functions (in programming) provide abstraction, views can be used to create abstraction.

Also, just like functions, views can be nested, thus one view can aggregate data from other views.

Without the use of views it would be much harder to normalise databases above second normal form.

Views can make it easier to create lossless join decomposition.

The correct answer to this question is B. Database views.

A database view is a logical or virtual table that is dynamically generated based on a query that selects specific columns and rows from one or more existing tables in a database. It presents a specific perspective on the underlying data and can be used to restrict the information that a user can access in a database.

Database views are commonly used for security purposes to provide access to a subset of data for a particular user or group of users. By using views, database administrators can control the data that is visible to different users without having to create separate copies of the data.

For example, a database administrator may create a view that selects only the customer names and addresses from a larger table that also includes sensitive financial data. They can then grant access to the view to customer service representatives who need to access the customer information, but not the financial data.

In addition to security, views can also be used to simplify complex data structures, provide a consistent interface to data, and improve performance by reducing the amount of data that needs to be queried.

Therefore, database views are a useful tool for database administrators to implement database security and provide access to restricted information to specific users.