Explore topic-wise MCQs in Engineering.

An entity instance of a subtype represents the same entity instance of a supertype.

An ERD that has had the entities clustered will display more entities.

Total specialization is represented by double lines between the supertype and subtype on an EER.

Data descriptions are stored in a central location called the depository.

Stored representations of objects and events that have meaning and importance in the user's environment are known as a database.

Backward recovery is used to reverse the changes made by transactions that have aborted, or terminated abnormally.

Incorrect data is easy to detect.

With concurrent processing involving updates, a database with concurrency control will be compromised due to interference between users.

A disaster recovery plan does not need to include the shipment of database backups to other sites.

Databases are not the property of a single function or individual within the organization.

Data modeling and database design are key responsibilities of data and data base administration.

Information repositories are replacing data dictionaries in many organizations.

Queries that do full table scans should be avoided.

The restore/rerun technique involves reprocessing the day's transactions up to the point of failure.

Another name for multimedia data is unstructured data.

The most common source of database failures in an organization is the failure to implement a strong database administration function.

The primary mechanism for providing context for data is metadata.

A workgroup typically comprises between 25 and 100 persons.

The source of the data is sometimes called the system of record.

Data quality problems currently cost U.S. businesses some $60 million each year (Hudica, 2003).

Stand-alone databases exhibit many of the same advantages common to file processing systems.

The database approach requires additional costs and risks.

Data scrubbing can help upgrade data quality; it is not a long-term solution to the data quality problem.

Every key used to join the fact table with a dimensional table should be a surrogate key.

Derived data are detailed, current data intended to be the single, authoritative source for all decision support applications.

Joining is the process of partitioning data according to predefined criteria.

The role of the ETL process is to identify erroneous data and to fix them.

Data in the data warehouse are loaded and refreshed from operational systems.

Star schema is suited to online transaction processing, and therefore is generally used in operational systems, operational data stores, or an EDW.

Periodic data are data that are physically altered once added to the store.

A transaction log shows before and after images of records that have been modified by transactions.

The greatest threat to business security is often internal rather than external.

Authorization tables contain highly sensitive data and should be protected by stringent security rules.

An enterprise data model is a relational model that shows the high-level entities for the organization and associations among those entities.

Independent data marts are often created because an organization focuses on a series of short-term business objectives.

Data in operational systems are typically fragmented and inconsistent.

Most operational systems are based on the use of transient data.

Two basic constructs to link one piece of data with another piece of data: sequential storage and pointers.

Denormalization and clustering can work well to minimize data access time for small records.

The presentation logic component is responsible for formatting and presenting data on the user's screen or other output device, and for managing user input from a keyboard or other input device.

Every time attribute A appears, it is matched with the same value of attribute B, but not the same value of attribute C. Therefore, it is true that:

Scalar aggregate are multiple values returned from an SQL query that includes an aggregate function.

A relation is considered a:

The different classes of relations created by the technique for preventing modification anomalies are called:

A primary key is a composite key that was selected to be the main identifier for the relation.

The EXISTS keyword will be true if:

The use of the double NOT EXISTS can be used to find rows that do not match some specified condition.

When two transactions are being processed against the database at the same time they are termed concurrent transactions.

The lost update problem is when User A reads data that have been processed by a portion of a transaction from User B.

The JVM (Java virtual machine) interprets Java bytecode at run time.