CSS - PMS - CCE - PCS - Basic Computing
Database Basics
Which SQL command removes selected rows from a table?
A. DELETE
B. CREATE
C. SELECT
D. GRANT
Correct Answer: A
DELETE removes rows and can use a WHERE clause to choose which rows are removed.
CSS - PMS - CCE - PCS - Basic Computing
Database Basics
Which SQL command changes existing records?
A. UPDATE
B. SELECT
C. CREATE
D. COMMIT
Correct Answer: A
UPDATE changes values in existing rows, usually based on a WHERE condition.
CSS - PMS - CCE - PCS - Basic Computing
Database Basics
Which SQL command adds a new record to a table?
A. INSERT
B. UPDATE
C. ALTER
D. GRANT
Correct Answer: A
INSERT adds new rows to a table.
CSS - PMS - CCE - PCS - Basic Computing
Database Basics
Which SQL command retrieves data from a table?
A. SELECT
B. INSERT
C. DELETE
D. DROP
Correct Answer: A
SELECT is used to retrieve rows and columns from one or more tables.
CSS - PMS - CCE - PCS - Basic Computing
Database Basics
What does SQL stand for?
A. Structured Query Language
B. Simple Question Logic
C. System Quality Link
D. Sequential Queue Language
Correct Answer: A
SQL stands for Structured Query Language and is used to work with relational databases.
CSS - PMS - CCE - PCS - Basic Computing
Database Basics
A decomposition that allows the original table to be reconstructed without losing information is:
A. Lossless decomposition
B. Destructive deletion
C. Data encryption
D. Circular backup
Correct Answer: A
Lossless decomposition divides a table while preserving all information and valid relationships.
CSS - PMS - CCE - PCS - Basic Computing
Database Basics
A possible disadvantage of heavy normalization is:
A. More joins may be required
B. Primary keys become impossible
C. The database cannot store text
D. All security is removed
Correct Answer: A
Highly normalized designs may require more table joins, which can make queries more complex.
CSS - PMS - CCE - PCS - Basic Computing
Database Basics
A relationship in which one attribute determines another is called a:
A. Functional dependency
B. Visual dependency
C. Network address
D. File extension
Correct Answer: A
A functional dependency exists when the value of one attribute determines the value of another.
CSS - PMS - CCE - PCS - Basic Computing
Database Basics
Losing useful information when an unrelated row is deleted is a:
A. Deletion anomaly
B. Insertion anomaly
C. Primary-key benefit
D. Query optimization
Correct Answer: A
A deletion anomaly occurs when deleting one record unintentionally removes another important fact.
CSS - PMS - CCE - PCS - Basic Computing
Database Basics
Being unable to add a fact without adding unrelated data is an:
A. Insertion anomaly
B. Deletion anomaly
C. Sorting error
D. Join result
Correct Answer: A
An insertion anomaly occurs when table design prevents adding one fact independently.
CSS - PMS - CCE - PCS - Basic Computing
Database Basics
Changing the same fact in many rows can cause an:
A. Update anomaly
B. Index advantage
C. Backup benefit
D. Security role
Correct Answer: A
An update anomaly occurs when duplicated facts must be changed in multiple places and may become inconsistent.
CSS - PMS - CCE - PCS - Basic Computing
Database Basics
The intentional addition of redundancy for performance is called:
A. Denormalization
B. Normalization
C. Encryption
D. Validation
Correct Answer: A
Denormalization deliberately combines or duplicates data to reduce joins and improve read performance.
CSS - PMS - CCE - PCS - Basic Computing
Database Basics
Boyce-Codd Normal Form requires every determinant to be a:
A. Candidate key
B. Foreign key only
C. Calculated field
D. Report heading
Correct Answer: A
BCNF requires every determinant in a functional dependency to be a candidate key.
CSS - PMS - CCE - PCS - Basic Computing
Database Basics
A transitive dependency occurs when a non-key attribute depends on:
A. Another non-key attribute
B. Only the primary key directly
C. A backup device
D. The database password
Correct Answer: A
A transitive dependency exists when one non-key attribute determines another non-key attribute.
CSS - PMS - CCE - PCS - Basic Computing
Database Basics
Third Normal Form removes:
A. Transitive dependencies
B. All candidate keys
C. Every relationship
D. All numeric values
Correct Answer: A
Third Normal Form requires 2NF and removes transitive dependencies among non-key attributes.
CSS - PMS - CCE - PCS - Basic Computing
Database Basics
A partial dependency occurs when a non-key attribute depends on:
A. Only part of a composite key
B. The entire candidate key
C. No attribute
D. A report title
Correct Answer: A
Partial dependency means a non-key field depends on only one part of a composite key.
CSS - PMS - CCE - PCS - Basic Computing
Database Basics
Second Normal Form removes:
A. Partial dependencies
B. All primary keys
C. All foreign keys
D. Every text value
Correct Answer: A
Second Normal Form requires 1NF and removes partial dependency on part of a composite key.
CSS - PMS - CCE - PCS - Basic Computing
Database Basics
Which of the following violates First Normal Form?
A. Storing several phone numbers in one field
B. Using a primary key
C. Storing one date in one field
D. Creating a foreign key
Correct Answer: A
Multiple values in one field are not atomic and therefore violate First Normal Form.
CSS - PMS - CCE - PCS - Basic Computing
Database Basics
A table is in First Normal Form when:
A. Each field contains atomic values
B. Every table has no rows
C. All values are encrypted
D. Every column contains multiple lists
Correct Answer: A
First Normal Form requires each cell to contain one atomic value and removes repeating groups.
CSS - PMS - CCE - PCS - Basic Computing
Database Basics
The process of organizing database tables to reduce redundancy is called:
A. Normalization
B. Encryption
C. Compilation
D. Pagination
Correct Answer: A
Normalization organizes data into well-structured tables to reduce duplication and anomalies.