I need help with this database worksheet. Thanks in advance!

True$/$False Questions $(2$ points each$)$

$1.$ A composite primary key is required for every table in a normalized database schema.

$2.$ Data normalization always reduces query performance.

$3.$ The HAVING clause can be used without a GROUP BY statement in SQL$.$

$4.$ A foreign key in one table must always refer to the primary key of another table.

$5.$ Denormalization in database design improves performance but sacrifices data integrity.

$6.$ Graph databases cannot handle schema changes as effectively as relational databases.

$7.$ SQL window functions are evaluated before WHERE conditions in a query.

$8.$ ACID compliance ensures that transactions are always performed in isolation, regardless of system failure.

$9.$ The relational algebra "natural join" operation will always include all columns

from both tables.

$10.$ Sharding in NoSQL databases improves scalability but can introduce consistency

issues.

Multiple Choice Questions $(3$ points each$)$

Which of the following is an advantage of a snowflake schema compared to a star

schema?

a$.$ Simpler queries

b$.$ Reduced data redundancy

c$.$ Increased performance

d$.$ Easier visualization

What does the UNION ALL operator do in SQL$?$

a$.$ Combines two queries and removes duplicates

b$.$ Combines two queries without removing duplicates

c$.$ Returns the intersection of two queries

d$.$ Returns the Cartesian product of two queries

Which scenario is most suited to using a graph database?

a$.$ Analyzing sales transactions

b$.$ Modeling hierarchical data like a company organization chart

c$.$ Recommending products based on purchase patterns

d$.$ Tracking real$-$time social network interactions

Which of the following is not a valid SQL data type?

a$.$ BOOLEAN

b$.$ STRING

c$.$ INTEGER

d$.$ FLOAT

What does the EXCEPT operator do in SQL$?$

a$.$ Combines results from two queries and removes duplicates

b$.$ Returns rows present in the first query but not the second

c$.$ Returns rows present in both queries

d$.$ Returns the Cartesian product of two queries

Which of these ensures a column value matches a specific format in SQL$?$

a$.$ CHECK constraint

b$.$ FOREIGN KEY constraint

c$.$ DEFAULT constraint

d$.$ INDEX

Which relational algebra operation returns tuples from one relation that do not

appear in another?

a$.$ Division

b$.$ Difference

c$.$ Projection

d$.$ Selection

Which property of ACID ensures data consistency when multiple transactions

occur simultaneously?

a$.$ Atomicity

b$.$ Consistency

c$.$ Isolation

d$.$ Durability

Which of the following best describes ETL in a data warehousing context?

a$.$ A process for real$-$time querying of operational data

b$.$ A method for encrypting and securing sensitive data

c$.$ The sequence of Extracting, Transforming, and Loading data into a warehouse

d$.$ A strategy for partitioning large datasets across multiple servers

Which command in SQL rolls back a transaction?

a$.$ SAVEPOINT

b$.$ COMMIT

c$.$ ROLLBACK

d$.$ BEGIN TRANSACTION