The Database Environment Questions and Answers

Answer: D

Correct answer: All of the above.

A database serving many people must be right, must be there when needed, must be recoverable after a failure, and must let each person see only what they should. None of the four can be dropped: an available database that is inaccurate is worse than useless, and an accurate one that cannot be recovered is a liability.

Answer: A

Correct answer: a graphical model that shows the high-level entities for an organization.

Both halves matter. It is graphical, so it can be read and validated by people who are not database specialists; and it shows high-level entities only, since a model containing every entity in the organisation would be unreadable and would not survive contact with change.

Answer: A

Correct answer: True

Data without context is a number without a meaning. Metadata supplies that context: what the item is called, what it means, what units it is in, where it came from and what it may legitimately contain. This is why the repository is central to a warehouse and to data quality generally.

Answer: A

Correct answer: The use of Internet protocols with limited access to company data by the company's customers and suppliers.

An extranet extends the internal network outward to named trading partners, using the same protocols as the public internet but with access controlled and limited. An intranet is the same technology restricted to people within the organisation; the difference is who is admitted, not what is used.

Answer: D

Correct answer: program-data dependency.

Program-data independence is the advantage - the descriptions live in the catalogue rather than in each program, so a change to the data does not require every program to be rewritten. Dependence is the file-processing defect that the database approach exists to remove, so it is the odd one out here.

Answer: B

Correct answer: historical operational data.

A warehouse accumulates what the operational systems recorded, so it holds the past rather than the present. That is what makes trend and comparison possible, and it is why the warehouse is loaded from the operational systems periodically rather than entered directly - the operational systems hold the current state and overwrite it.

Answer: C

Correct answer: Data is represented by tables.

The relation is the model’s single structure, presented as a table of rows and columns, and everything else follows from it. The other two options are the opposite of the case for the relational model: data is reached by declarative query rather than navigation, and a simple query needs no program at all.

Answer: B

Correct answer: False

The central store of data descriptions is a repository. Depository is not the term used, and the distinction matters because the repository is a real component with a defined role - holding the metadata that gives the data its meaning.

Answer: C

Correct answer: Department

Departmental databases outnumber the others because most information needs are departmental: a size that justifies a proper shared database but not an enterprise-wide one. Personal databases are numerous but trivial, and enterprise databases are few because there are few enterprises relative to departments.

Answer: A

Correct answer: True

The system of record is the authoritative source for a piece of data - the place where it is first captured and against which any disagreement is settled. Naming it explicitly matters in an environment with copies in warehouses, marts and reports, since without it there is no way to say which copy is right.