Ohio Database Specialist Practice Exam

Ohio Database Specialist Practice Exam Questions And Correct Answers (Verified Answers) Plus Rationales 2025|2026 Q&A | Instant Download Pdf

• Which SQL command is used to remove a table from a database?

A. DELETE

B. DROP

C. TRUNCATE

D. REMOVE

Answer: B. DROP

Rationale: The DROP command permanently removes the table structure

and all its data from the database.

• Which normal form eliminates transitive dependencies?

A. 1NF

B. 2NF

C. 3NF 1 / 3

D. BCNF

Rationale: Third Normal Form (3NF) ensures no transitive dependencies

between non-key attributes.

• What is the default isolation level in most RDBMS systems like SQL

Server?

A. READ UNCOMMITTED

B. READ COMMITTED

C. REPEATABLE READ

D. SERIALIZABLE

Rationale: READ COMMITTED prevents dirty reads by default in many

systems such as SQL Server and Oracle.

• Which of the following ensures uniqueness in a column?

A. FOREIGN KEY

B. UNIQUE CONSTRAINT

C. CHECK

D. DEFAULT

Rationale: UNIQUE ensures no duplicate values in a column or set of

columns.

• Which SQL clause filters rows after grouping?

A. WHERE

B. SELECT

C. HAVING 2 / 3

D. GROUP BY

Rationale: HAVING applies conditions to grouped data after aggregation.

• What is a surrogate key?
• A foreign key
• A system-generated unique key
• A natural key
• A composite key

Rationale: Surrogate keys are artificial keys like auto-increment integers

used to uniquely identify records.

7. In ER modeling, a weak entity requires:

• A surrogate key
• A strong entity and a partial key
• A foreign key only
• No key

Rationale: Weak entities depend on a strong entity for existence and use a

partial key for identification.

• What command is used to undo a transaction?

A. SAVEPOINT

B. ROLLBACK

C. COMMIT

D. CANCEL

Rationale: ROLLBACK restores the database to its previous state before the

transaction began.

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