NYC Certified IT Administrator (Database) Exam Practice Questions And Correct Verified Answers Plus Rationales 2026 (GUARANTEED PASS)

NYC Certified IT Administrator (Database) Exam Practice
Questions And Correct Verified Answers Plus Rationales 2026
(GUARANTEED PASS)


Question 1
Which SQL command is used to remove all records from a table but keep
the table structure?
A) DELETE
B) TRUNCATE
C) DROP
D) REMOVE
VERIFIED ANSWER: B) TRUNCATE
Rationale: TRUNCATE removes all rows from a table without affecting its
structure, unlike DROP which deletes the table entirely, and DELETE which
can be slower and uses more transaction log space.


Question 2
What is the default port for MySQL database server?
A) 1521
B) 1433

,C) 3306
D) 5432
VERIFIED ANSWER: C) 3306
Rationale: MySQL uses port 3306 by default. Oracle uses 1521, SQL Server
uses 1433, and PostgreSQL uses 5432.


Question 3
Which SQL statement is used to modify existing data in a table?
A) INSERT
B) UPDATE
C) ALTER
D) MODIFY
VERIFIED ANSWER: B) UPDATE
Rationale: UPDATE is used to change existing rows in a table. INSERT adds
new rows, and ALTER changes table structure.


Question 4
In relational databases, a primary key must be:
A) Nullable
B) Duplicate allowed

,C) Foreign key
D) Unique and not null
VERIFIED ANSWER: D) Unique and not null
Rationale: A primary key uniquely identifies each record in a table and
cannot contain null values or duplicates.


Question 5
Which command in SQL is used to permanently remove a table and its
data?
A) DELETE
B) UPDATE
C) DROP TABLE
D) TRUNCATE
VERIFIED ANSWER: C) DROP TABLE
Rationale: DROP TABLE deletes the table structure and all its data
permanently. TRUNCATE removes data only.


Question 6
Which of the following is a non-relational database?

, A) MySQL
B) PostgreSQL
C) Oracle
D) MongoDB
VERIFIED ANSWER: D) MongoDB
Rationale: MongoDB is a NoSQL (non-relational) database that stores data
as documents in BSON format rather than in tables with rows and
columns.


Question 7
Which SQL clause is used to filter rows returned by a query?
A) FROM
B) WHERE
C) GROUP BY
D) HAVING
VERIFIED ANSWER: B) WHERE
Rationale: WHERE filters rows based on specified conditions before any
grouping occurs. HAVING filters after grouping.


Question 8