WorksheetsRDBMS Fundamentals and Relational Algebra
Total questions: 30
Worksheet time: 15mins
Which statement best defines a Relational Database Management System (RDBMS)?
A file system for unstructured documents
Software that maintains a relational database
A programming language for graphics design
Hardware used to store magnetic tapes
Which ACID property ensures all parts of a transaction succeed or none do?
Consistency guarantees faster performance
Durability allows reversible persistence
Atomicity ensures all-or-nothing execution
Isolation merges transactions together
What does Data Integrity primarily aim to ensure in databases?
Queries run at maximum speed
Data is accurate and consistent
Tables never require indexing
Backups are created nightly
In table vocabulary, what is an attribute?
A column header such as Student_ID
A single record stored as a row
The count of rows in a table
The allowed range of values
Which term refers to the set of allowable values for a column?
Cardinality sets numeric precision
Domain defines the allowable values
Tuple lists the row constraints
Degree specifies row uniqueness
Cardinality of a relation refers to which quantity?
Number of keys defined per table
Number of distinct domains used
Number of attributes per tuple
Number of tuples in the relation
Which operation in relational algebra filters rows based on a condition like Age > 20?
Select filters rows by a predicate
Union joins unrelated structures
Project removes duplicate schemas
Intersect creates computed columns
Project in relational algebra performs which action?
Returns only common rows across tables
Combines rows from different schemas
Filters records meeting a condition
Chooses specific columns from a table
Union can combine two tables only when what requirement is met?
Both tables share the same structure
Both tables use the same primary key
Both tables contain no null values
Both tables have equal cardinality
Which operation returns only rows present in both input tables?
Intersect returns common rows only
Join returns every possible pairing
Select returns sorted intersections
Project returns selected attributes
Join combines two tables based on what criterion?
Equal degrees for the two relations
Identical tuples across both tables
A related column between the tables
Matching domain ranges for columns
A relation with 5 columns and 200 rows has which degree and cardinality?
Degree 1 and cardinality 205
Degree 200 and cardinality 5
Degree 205 and cardinality 1
Degree 5 and cardinality 200
Which statement best describes Entity Relationship (ER) modeling?
A diagram of tables and indexes only
A low-level storage layout for disk pages
A high-level view of entities and connections
A process for tuning query execution plans
What is the primary focus of a semantic model?
Physical storage performance and caching
Syntax of SQL and procedural extensions
Meaning of data and real-world relationships
Normalization rules for eliminating redundancy
Which description fits a generic model?
Domain-specific logic for a single industry
Generalized representation across many domains
Executable code for database drivers
Graph algorithms for routing and pathfinding
Which statement correctly defines a Super Key?
Only the designer-selected unique identifier
Any set of columns that uniquely identifies a row
Any single column with numeric values
A column that references another table’s key
Which option captures the essence of a Candidate Key?
A minimal Super Key without unnecessary columns
A foreign reference used to create table links
A non-unique attribute used for sorting records
A composite index created for query speed
What distinguishes a Primary Key from other Candidate Keys?
It is created automatically by the database engine
It always contains multiple columns and can be null
It only exists in many-to-many relationship tables
It is chosen as the unique identifier and cannot be null
Which statement describes a Foreign Key?
A column pointing to another table’s Primary Key
A field that stores encrypted credentials
A key used solely for indexing text columns
A table’s mandatory unique identifier
A designer proposes a key {email, username, user_id}. It uniquely identifies rows, but user_id alone is also unique. Which classification is most accurate for the proposed key?
Foreign Key because it references user_id
Minimal Super Key and a Candidate Key
Primary Key because it contains user_id
Non-minimal Super Key but not a Candidate Key
In an ER model, which pairing best represents entities and relationships?
Entities as columns; relationships as constraints
Entities as things; relationships as connections
Entities as actions; relationships as procedures
Entities as files; relationships as directories
Which statement best defines entity integrity in a relational table?
Every foreign key must reference a primary key
All attributes in a row must be unique
No component of a primary key can be null
Each table must have at least one foreign key
A grade record contains Student_ID as a foreign key. Which action violates referential integrity?
Inserting a grade for an existing Student_ID
Leaving Student_ID null for a missing grade
Updating Student_ID to a nonexisting value
Deleting a grade for a withdrawn student
What is the primary goal of integrity constraints in databases?
Eliminating the need for indexes
Reducing storage across all tables
Preventing invalid or garbage data
Speeding up complex analytical queries
Which scenario illustrates a one-to-one (1:1) relationship?
One person has one passport
One customer places many orders
Many students enroll in many courses
One course has many students
Which relationship type is most commonly seen between Customer and Order entities?
One-to-one with optional participation
One-to-many from Order to Customer
One-to-many from Customer to Order
Many-to-many using a junction table
Why do many-to-many (M:N) relationships typically require a junction table in an RDBMS?
To store derived attributes for faster reports
To break M:N into two 1:N relationships
To enforce unique values across all columns
To allow nullable primary keys when needed
You are designing a Student–Course schema. Which structure correctly enforces enrollments?
Course has a foreign key to Student only
Student has a foreign key to Course only
An Enrollment table links Student and Course
A shared primary key across Student and Course
A table uses a composite primary key (A, B). Which insert violates entity integrity?
Inserting a row with A and B both unique
Inserting a row with A and B both not null
Inserting a row with A not null and B null
Inserting a row with a new unique A, B pair
A database must prevent orphan rows in a child table. Which mechanism directly addresses this?
Unique constraints on candidate keys
Indexes on frequently joined columns
Check constraints on numeric ranges
Referential integrity on foreign keys
