Database Fundamentals Quiz
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Questions and Answers

What does the term 'cardinality' refer to in the context of database relationships?

  • The number of entities that participate in a relationship (correct)
  • The number of attributes per entity
  • The type of relationship established
  • The degree of relationship between entities

    • Which operation in relational algebra is used to extract specific columns from a table?

  • SELECT (σ)
  • JOIN
  • INTERSECTION
  • PROJECT (π) (correct)

    • What is the primary shape used to represent attributes in an ER diagram?

  • Ellipse (correct)
  • Circle
  • Diamond
  • Rectangle

    • What is the result of mapping a many-to-many relationship to a relational schema?

    <p>A new intermediary table is created</p> Signup and view all the answers

    Which of the following symbols indicates a primary key in an ER diagram?

    <p>Underlined attribute</p> Signup and view all the answers

    What type of relationship exists when one entity is linked to multiple instances of another entity?

    <p>One-to-Many</p> Signup and view all the answers

    Which of the following is not considered a key step in designing an ER diagram?

    <p>Creating file structures</p> Signup and view all the answers

    What type of relationship is indicated by a diagram form where a single entity is related to itself?

    <p>Self-referential</p> Signup and view all the answers

    What is the purpose of using a weak entity in an entity relationship model?

    <p>It depends on a strong entity for its identification.</p> Signup and view all the answers

    What does the SQL command 'DROP' specifically do?

    <p>Permanently deletes both the table and its data.</p> Signup and view all the answers

    Which SQL command should you use to modify an existing table's structure?

    <p>ALTER</p> Signup and view all the answers

    In SQL, which clause would you use to determine the source table for retrieval operations?

    <p>FROM</p> Signup and view all the answers

    Which of the following statements about database normalization is correct?

    <p>Its goal is to improve data integrity and reduce redundancy.</p> Signup and view all the answers

    What action does the SQL command 'UPDATE' perform?

    <p>Modifies existing data in a table.</p> Signup and view all the answers

    A characteristic of a normalized database is that it reduces redundancy. What is another potential outcome of normalization?

    <p>Minimized data anomalies.</p> Signup and view all the answers

    Which of the following is NOT a feature of SQL?

    <p>Sending emails.</p> Signup and view all the answers

    Which feature differentiates NoSQL databases from traditional relational databases?

    <p>They support flexible, schema-less data models</p> Signup and view all the answers

    What command correctly initiates the MySQL server using the command line?

    <p>service mysql start</p> Signup and view all the answers

    In the context of database entities, what is the primary role of an attribute?

    <p>To describe a characteristic or property of an entity</p> Signup and view all the answers

    Which option is NOT a typical function of a Database Management System (DBMS)?

    <p>Maintaining hardware efficiency</p> Signup and view all the answers

    What is meant by the primary key in a database table?

    <p>It uniquely identifies each record in a database table</p> Signup and view all the answers

    Which of the following examples demonstrates a correct classification of databases?

    <p>PostgreSQL is a relational database</p> Signup and view all the answers

    What does the term 'schema' refer to in the context of a database?

    <p>It acts as a blueprint for the database structure</p> Signup and view all the answers

    Which command is primarily associated with managing the MySQL server’s status?

    <p>systemctl mysql status</p> Signup and view all the answers

    Which of the following accurately describes a table in Second Normal Form (2NF)?

    <p>It is in 1NF and has no partial dependencies</p> Signup and view all the answers

    Which condition must be satisfied for a table to be in Third Normal Form (3NF)?

    <p>It must be in 2NF and have no transitive dependencies</p> Signup and view all the answers

    What characterizes BCNF in relation to previous normal forms?

    <p>It is a stricter version of 3NF</p> Signup and view all the answers

    What condition indicates that a table violates BCNF?

    <p>A non-trivial functional dependency exists with a non-candidate key</p> Signup and view all the answers

    What is the primary goal of denormalization in database design?

    <p>To reduce the number of tables by combining them</p> Signup and view all the answers

    Which of the following is a common disadvantage of denormalization?

    <p>Increased data redundancy</p> Signup and view all the answers

    In which scenario is denormalization most appropriate?

    <p>When read performance is critical</p> Signup and view all the answers

    Which aspect does a well-designed ER Diagram for the given situation not need to include?

    <p>Foreign keys for each attribute</p> Signup and view all the answers

    Study Notes

    Database Fundamentals

    • Database: An organized collection of electronically stored data.

    • DBMS (Database Management System): A system for managing and accessing data within a database. Functions include data storage, retrieval, and security.

    • Database Entities: A significant thing or concept.

    • Database Attributes: The characteristics or properties of an entity.

    • Tuple: A single row in a relational database table.

    • Relational Database: An organized database structure using tables, rows, and columns to link data between tables with relationships.

    • NoSQL Database: A database that offers flexibility, which supports unstructured/semi-structured data models. Optimized for managing large, varied datasets.

    • Primary Key: A unique identifier for a record in a table.

    • Foreign Key: A field in one table that links to the primary key of another table.

    • MySQL Workbench: A graphical interface for managing MySQL databases.

    • MySQL: A relational database management system that is based on a relational database model.

    • MongoDB: A NoSQL database.

    • SQL (Structured Query Language): A language used for interacting with relational databases. Common use cases include data retrieval, creation and modification of tables, and storage.

    • SELECT: SQL command for retrieving data from a database table.

    • CREATE TABLE: SQL command for creating a new table.

    • ALTER TABLE: SQL command for modifying an existing table's schema (structure.)

    • INSERT: SQL command for adding new rows to a table.

    • UPDATE: SQL command for modifying existing data within a table.

    • DELETE: SQL command for removing rows from a table.

    Database Normalization

    • Database Normalization: A process used to organize data in a database to reduce redundancy, improving data integrity.

    • First Normal Form (1NF): A database is in 1NF if it does not contain repeating groups of data. Crucial to eliminate redundancy and ensure data consistency.

    • Second Normal Form (2NF): A database is in 2NF if it is in 1NF and contains no partial dependencies on the primary key.

    • Third Normal Form (3NF): If it's in 2NF and doesn't contain transitive dependencies; this step eliminates further redundancies.

    • Boyce-Codd Normal Form (BCNF): A stricter form of 3NF to further reduce data redundancy.

    ER Diagrams

    • ER Diagram (Entity-Relationship Diagram): A visual representation of entities, their attributes, and relationships between them in a database. A key tool for planning and designing databases.

    • Entities: Represented as rectangles.

    • Attributes: Represented as ovals, linked to the corresponding entities.

    • Relationships: Represented using connecting lines between entities, providing a detailed representation of links between entities within the database.

    Data Modeling

    • Identifying Entities: The process of determining the key concepts or objects in a system that need representation in the database.

    • Identifying Attributes: Determining the key characteristics that describe each entity.

    • Defining Relationships: Defining the ways the entities connect with each other.

    • Cardinality: Defining the number of entities that participate in a relationship.

    • Real-World Entity: A physical, tangible, or conceptual item in a given context.

    Example Scenario

    • Different Departments and Centers: A company with various departments or centers, each having specific personnel. Database tables for storing employee information, department details, and the relationships between them would be needed in a comprehensive system.

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    Fundamentals of Database Final Exam Reviewer PDF

    Description

    Test your knowledge on the basics of database systems, including key concepts like DBMS, entities, attributes, and relational structures. This quiz covers essential terms and definitions necessary for understanding databases, whether relational or NoSQL.

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