North Carolina SQL Database Developer
Certification Exam Question and correct
answers (verified answers 100%) Q&A
2026/2027 INSTANT DOWNLOAD PDF
1. Which SQL command is used to retrieve data from a database table?
A. INSERT
B. UPDATE
C. SELECT
D. DELETE
Correct Answer: C. SELECT
Rationale: The SELECT statement is used to query and retrieve data from one or
more database tables.
2. Which database object is primarily used to store structured data?
A. Trigger
B. Table
C. View
D. Index
Correct Answer: B. Table
Rationale: Tables store data in rows and columns and are the fundamental storage
objects in relational databases.
3. What is the purpose of a primary key in a database table?
,A. Encrypt data
B. Create duplicate records
C. Uniquely identify each row
D. Improve network speed
Correct Answer: C. Uniquely identify each row
Rationale: A primary key ensures each record has a unique identifier and prevents
duplicate rows.
4. Which SQL constraint prevents NULL values from being inserted into a
column?
A. UNIQUE
B. CHECK
C. NOT NULL
D. DEFAULT
Correct Answer: C. NOT NULL
Rationale: The NOT NULL constraint requires a column to always contain a value.
5. Which SQL statement is used to add new records into a table?
A. CREATE
B. INSERT
C. ALTER
D. MERGE
Correct Answer: B. INSERT
Rationale: INSERT adds new rows of data into an existing database table.
6. What does DDL stand for in SQL?
,A. Data Definition Language
B. Data Display Language
C. Database Development Logic
D. Data Deployment Layer
Correct Answer: A. Data Definition Language
Rationale: DDL defines database structures using commands such as CREATE,
ALTER, and DROP.
7. Which SQL command modifies existing records?
A. MODIFY
B. UPDATE
C. CHANGE
D. ALTER
Correct Answer: B. UPDATE
Rationale: UPDATE changes existing data values stored in table rows.
8. Which SQL clause is used to filter rows returned by a query?
A. ORDER BY
B. GROUP BY
C. WHERE
D. HAVING
Correct Answer: C. WHERE
Rationale: WHERE filters individual rows based on specified conditions.
9. Which keyword removes duplicate records from query results?
, A. UNIQUE
B. DISTINCT
C. DIFFERENT
D. REMOVE
Correct Answer: B. DISTINCT
Rationale: DISTINCT eliminates duplicate values from the result set.
10. Which SQL statement permanently removes a table?
A. DELETE TABLE
B. REMOVE TABLE
C. DROP TABLE
D. CLEAR TABLE
Correct Answer: C. DROP TABLE
Rationale: DROP TABLE deletes the table structure and its stored data
permanently.
11. What is the main purpose of database normalization?
A. Increase data duplication
B. Reduce redundancy
C. Remove security controls
D. Increase file size
Correct Answer: B. Reduce redundancy
Rationale: Normalization organizes data to reduce duplication and improve
consistency.
12. Which normal form removes repeating groups of data?
Certification Exam Question and correct
answers (verified answers 100%) Q&A
2026/2027 INSTANT DOWNLOAD PDF
1. Which SQL command is used to retrieve data from a database table?
A. INSERT
B. UPDATE
C. SELECT
D. DELETE
Correct Answer: C. SELECT
Rationale: The SELECT statement is used to query and retrieve data from one or
more database tables.
2. Which database object is primarily used to store structured data?
A. Trigger
B. Table
C. View
D. Index
Correct Answer: B. Table
Rationale: Tables store data in rows and columns and are the fundamental storage
objects in relational databases.
3. What is the purpose of a primary key in a database table?
,A. Encrypt data
B. Create duplicate records
C. Uniquely identify each row
D. Improve network speed
Correct Answer: C. Uniquely identify each row
Rationale: A primary key ensures each record has a unique identifier and prevents
duplicate rows.
4. Which SQL constraint prevents NULL values from being inserted into a
column?
A. UNIQUE
B. CHECK
C. NOT NULL
D. DEFAULT
Correct Answer: C. NOT NULL
Rationale: The NOT NULL constraint requires a column to always contain a value.
5. Which SQL statement is used to add new records into a table?
A. CREATE
B. INSERT
C. ALTER
D. MERGE
Correct Answer: B. INSERT
Rationale: INSERT adds new rows of data into an existing database table.
6. What does DDL stand for in SQL?
,A. Data Definition Language
B. Data Display Language
C. Database Development Logic
D. Data Deployment Layer
Correct Answer: A. Data Definition Language
Rationale: DDL defines database structures using commands such as CREATE,
ALTER, and DROP.
7. Which SQL command modifies existing records?
A. MODIFY
B. UPDATE
C. CHANGE
D. ALTER
Correct Answer: B. UPDATE
Rationale: UPDATE changes existing data values stored in table rows.
8. Which SQL clause is used to filter rows returned by a query?
A. ORDER BY
B. GROUP BY
C. WHERE
D. HAVING
Correct Answer: C. WHERE
Rationale: WHERE filters individual rows based on specified conditions.
9. Which keyword removes duplicate records from query results?
, A. UNIQUE
B. DISTINCT
C. DIFFERENT
D. REMOVE
Correct Answer: B. DISTINCT
Rationale: DISTINCT eliminates duplicate values from the result set.
10. Which SQL statement permanently removes a table?
A. DELETE TABLE
B. REMOVE TABLE
C. DROP TABLE
D. CLEAR TABLE
Correct Answer: C. DROP TABLE
Rationale: DROP TABLE deletes the table structure and its stored data
permanently.
11. What is the main purpose of database normalization?
A. Increase data duplication
B. Reduce redundancy
C. Remove security controls
D. Increase file size
Correct Answer: B. Reduce redundancy
Rationale: Normalization organizes data to reduce duplication and improve
consistency.
12. Which normal form removes repeating groups of data?
