DBMS Midterm Exam

Which statement best distinguishes a database from a spreadsheet?

A database can enforce relationships and rules for multiple users.

Which component checks user access, processes requests, enforces rules, and returns results?

DMBS

Which term describes the blueprint or structure of a database?

Schema

In a relational table, a tuple is:

One Row

In a relational table, an attribute is:

A Column

What is the main purpose of a primary key?

Uniquely identify each row

Which rule requires primary key values to be unique and non-null?

Entity integrity

Which rule requires a non-null foreign key to match an existing referenced key

Referential integrity

STUDENT.ProgramID references PROGRAM.ProgramID. STUDENT.ProgramID is a:

Foreign key

Which SQL clause identifies the columns to display?

SELECT

Which SQL clause identifies the source table?

FROM

In the logical processing order of a basic query, which clause is processed first?

FROM

Which condition includes prices of exactly $50 and exactly $100?

Price >= 50 AND Price <= 100

Why are parentheses useful in a condition containing both AND and OR?

They make the intended grouping explicit

What does SELECT DISTINCT do?

Removes duplicate result rows

What does an INNER JOIN return?

Only rows whose join condition matches

In a multi-table query, what is the purpose of the ON clause?

Define how rows from two tables match

Before running an UPDATE or DELETE, which action provides the best immediate safety check?

Run the intended condition as a SELECT

A STUDENT and COURSE_SECTION relationship is many-to-many. Which design resolves it?

Create ENROLLMENT with both identifiers

Why does Grade belong in ENROLLMENT?

Grade is determined by one student taking one section.

Which change is required by First Normal Form?

Place one value in each cell

ENROLLMENT has key (StudentID, CourseID). StudentName depends only on StudentID. What problem exists?

A partial dependency that violates 2NF

T/F: SQL is declarative because users specify the result they want rather than every processing step.

True

T/F: Referential integrity permits a non-null foreign key to reference a primary-key value that does not exist.

False

T/F: A bank that permits joint accounts may require a many-to-many relationship between CUSTOMER and ACCOUNT.

True

T/F: In Third Normal Form, a non-key attribute may depend on another non-key attribute.

False

T/F: Deleting the last enrollment from a poorly designed combined table can accidentally remove the only stored facts about a course.

True