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WorksheetsDatabase Management System Quiz
Total questions: 47
Worksheet time: 16mins
List the primary goal of a Database Management System (DBMS).
To store and retrieve data efficiently
To develop web pages
To connect only to hardware devices
To encrypt network data
Identify the component that ensures data consistency during a system crash.
Transaction management
Web server
Cloud client
File scanner
Explain why data abstraction is important in DBMS.
It hides storage details from users
It increases redundancy
It slows down performance
It deletes metadata
Select the view that provides only a partial perspective of the database.
View level
Logical level
Physical level
Schema level
Name the language used to retrieve and manipulate data in SQL.
Data Manipulation Language (DML)
Data Creation Language (DCL)
Domain Modeling Language
Dynamic Markup Language
State the type of DML that specifies what data is needed, not how to get it.
Declarative
Procedural
Dynamic
Imperative
Classify the relational model under the following category.
Record-based data model
Object-oriented model
Semistructured model
Graph-based model
Compare relational and hierarchical models.
Relational uses tables; hierarchical uses tree structures
Both use graph representations
Relational uses recursion; hierarchical uses views
Hierarchical supports SQL
Express the meaning of "schema" in a database context.
Structural design of the database
A runtime instance of the data
A record of logs
A network of disks
Discuss the importance of primary keys in a relational model.
They uniquely identify tuples
They provide redundancy
They replace tables
They model relationships
Report the use of foreign keys in relational databases.
They maintain referential integrity
They delete primary keys
They define access roles
They alter schemas
List a major disadvantage of traditional file-based systems.
Data redundancy and inconsistency
High modularity
Easy concurrency
High normalization
Identify the abstraction level that describes how data is stored.
Physical level
Logical level
View level
External level
Explain the purpose of ER modeling.
To capture real-world entities and relationships
To optimize SQL joins
To define RAID levels
To manage user roles
Select the notation commonly used in ER diagrams.
Rectangles for entities
Diamonds for attributes
Circles for schemas
Arrows for relations
Name the type of attribute that can be broken into sub-parts.
Composite attribute
Derived attribute
Simple attribute
Null attribute
State what a relationship set represents.
A collection of relationships of the same type
A specific tuple
A group of users
A primary key
Classify relationships based on their cardinality.
One-to-one, one-to-many, many-to-many
Primary, secondary, tertiary
Internal, external, derived
Strong, weak, derived
Compare strong and weak entities.
Weak entities depend on strong ones for identification
Weak entities have more attributes
Strong entities lack keys
Weak entities always use triggers
Discuss why generalization is used in ER modeling.
To group similar entities into a higher-level entity
To remove redundant foreign keys
To speed up indexing
To normalize data
List the main components of relational algebra.
Selection, projection, union, set difference
Assignment, loop, join, thread
Commit, rollback, pause, fetch
Input, output, allocate, release
Identify the symbol for selection in relational algebra.
σ (sigma)
π (pi)
∪ (union)
ρ (rho)
Explain the use of π (pi) in relational algebra.
It projects specific attributes from a relation
It joins relations
It renames attributes
It selects tuples
Select the correct representation of a Cartesian product.
R × S
R ∪ S
R − S
R ⨝ S
Name the operation that returns common tuples between relations.
Intersection
Set difference
Rename
Aggregation
State what a natural join does.
Combines relations based on common attribute names
Merges unrelated data
Projects all attributes
Returns unrelated keys
Classify the join operations in relational algebra.
Theta join, equijoin, natural join
Super join, mega join, weak join
Horizontal join, vertical join, diagonal join
External join, internal join, flat join
Compare tuple relational calculus and domain relational calculus.
Tuple uses variables for tuples; domain uses variables for values
Tuple is faster
Domain is only used in C++
Tuple doesn't support SQL
Express a formula in tuple relational calculus.
{t | P(t)}
SELECT * FROM t
{t.name | FROM t}
t := p
Discuss the safety of expressions in relational calculus.
Unsafe expressions may yield infinite results
Safe expressions are inefficient
Unsafe expressions return NULL
Safe expressions violate keys
Report the function of domain constraints.
They define valid attribute values
They restrict table joins
They manage locks
They compress data
List the uses of null values in relational databases.
Represent missing or unknown data
Store 0
Define relationships
Create primary keys
Identify the language used to define database schemas.
Data Definition Language (DDL)
HTML
JSON
AJAX
State a key difference between SQL and relational algebra.
SQL is declarative; relational algebra is procedural
SQL is only graphical
Algebra is specific to Oracle
SQL lacks joins
Classify query languages into the following types.
Procedural and nonprocedural
Graphical and textual
Tabular and relational
Inferred and enforced
Compare outer joins and inner joins.
Outer joins include unmatched rows
Inner joins include unmatched rows
Outer joins exclude foreign keys
Inner joins perform unions
Discuss the role of aliases in SQL.
They rename tables or columns temporarily
They change database names
They restrict joins
They define indexes
List reasons to use foreign keys.
Maintain referential integrity
Duplicate keys
Manage transactions
Normalize indexes
Identify the SQL clause used to filter tuples.
WHERE
HAVING
SELECT
ORDER
Explain the difference between COUNT(*) and COUNT(attribute).
COUNT(*) counts all rows; COUNT(attr) ignores NULLs
Both are identical
COUNT(attr) counts duplicates
COUNT(*) ignores NULLs
Select the SQL keyword used for grouping.
GROUP BY
ORDER BY
SELECT
UNION
Name the SQL clause used for filtering groups.
HAVING
WHERE
LIMIT
SORT
State a reason for using views in SQL.
Simplify complex queries
Increase physical size
Improve latency
Replace tables
Classify the three types of relational joins.
Inner, outer, natural
Vertical, horizontal, conditional
Literal, symbolic, reference
Flat, hierarchical, modular
Compare delete and truncate in SQL.
DELETE is slower and logs each row; TRUNCATE is faster
DELETE removes schema
TRUNCATE logs each row
DELETE resets auto-increment
Express the use of aggregate functions.
Perform calculations on groups
Validate records
Trigger procedures
Normalize columns
Discuss why a relation is considered a set.
It doesn't allow duplicate tuples
It uses loop iterations
It merges tuples on joins
It replaces attributes
