The Client-Server Database Questions and Answers

Answer: D

Correct answer: Complete applications can be written using QBE.

QBE has grown from a query interface into an environment in which whole applications are built - forms, reports and the logic joining them. The other options are all false: it is a visual environment by definition, it works perfectly well against a server, and it has never been standardised, so each product’s version differs.

Answer: A

Correct answer: True

Processing logic is where the application decides whether what it has been given makes sense: checking that values are within range and consistent with one another, and detecting errors before they reach the database. Placing it in a tier of its own means every client is validated by the same rules.

Answer: A

Correct answer: Database storage

The database server is responsible for storing and retrieving the data and for the access and integrity controls that go with it. Processing logic belongs to the application tier and presentation logic to the client - the point of the separation being that each can be changed without disturbing the others.

Answer: C

Correct answer: Data integrity improves as multiple applications access the same stored procedure.

One procedure enforcing a rule means every application enforces it identically, and it cannot be forgotten in one of them. The other options are the reverse of the truth: stored procedures reduce network traffic by sending a call rather than a series of statements, and they make the client thinner rather than thicker.

Answer: A

Correct answer: Client Layer

A server can host the database layer, the business logic layer, or both, but the client layer is by definition where the user sits and interacts. That is the one role a server does not perform, and the distinction is what the tiers are named for.

Answer: D

Correct answer: All of the above.

All three describe ODBC correctly. It defines a common programming interface so that an application can issue SQL without knowing which database it will reach; each vendor supplies a driver to make its product conform; and a connection requires the driver, the data source and the credentials to be in place before it can be established.

Answer: A

Correct answer: Manages file operations and is shared on a network.

A file server holds files and serves them to the machines on the network, which then do the processing themselves. This is what makes it different from a database server: the whole file crosses the network rather than the answer to a query, so the network carries far more traffic and the concurrency control is weak.

Answer: B

Correct answer: False

Waiting for a response in real time is synchronous behaviour. An asynchronous request is issued and the requester continues with other work, collecting the response later. The statement has given the definition of one under the name of the other.

Answer: A

Correct answer: True

The database server does all three: it stores the data, controls access to it, and performs the processing needed to answer a query - selecting, joining, aggregating - so that only the result crosses the network. That last point is what separates it from a file server, which ships whole files and leaves the work to the client.

Answer: A

Correct answer: New modules can be built to support specific business needs

Separating the application logic into its own tier means new business function can be added there without touching the client or the database, and the same logic serves every client. The other options misstate the effects - the client becomes thinner but the database server does not, and compiled SQL performance belongs to stored procedures rather than to the architecture.