Database Systems Overview
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Questions and Answers

Who designed the first general purpose DBMS?

  • Mark Zuckerberg
  • Bill Gates
  • Charles William Bachman III (correct)
  • Larry Ellison

    • What is the primary role of data management?

  • To analyze user behavior
  • To create software applications
  • To design network infrastructures
  • To ensure proper generation, storage, and retrieval of data (correct)

    • Which advantage of a DBMS emphasizes that application programs should not be exposed to data representation and storage details?

  • Data Security
  • Reduced Application Development Time
  • Data Administration
  • Data Independence (correct)

    • What type of database supports many users across various departments in an organization?

    <p>Enterprise Database</p> Signup and view all the answers

    Which term describes data about data?

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

    Which ACID property of a DBMS is defined as 'All or Nothing'?

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

    What is a multiuser database typically characterized by?

    <p>Fewer than 50 users</p> Signup and view all the answers

    What are raw facts referred to in data terminology?

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

    Which schema level comes between the user level and the physical storage view?

    <p>Conceptual Schema</p> Signup and view all the answers

    What term refers to the maximum number of times an instance in one entity can be associated with instances in a related entity?

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

    Which model depicts a set of one-to-many relationships between a parent and its children segments?

    <p>Hierarchical Model</p> Signup and view all the answers

    In database terminology, what describes an association between entities?

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

    Which of the following statements is true regarding independent entities?

    <p>They can exist on their own.</p> Signup and view all the answers

    What is the primary function of Data Definition Language (DDL) in the context of a database?

    <p>Defining schema components</p> Signup and view all the answers

    What is the characteristic of an entity in a database?

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

    Which generation of data model is represented by the File System?

    <p>1st Generation</p> Signup and view all the answers

    What does structural independence in a database imply?

    <p>Changes in the file structure do not affect application access to data.</p> Signup and view all the answers

    Which property ensures that ongoing transactions do not interfere with each other?

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

    What occurs when the same data is stored in multiple locations within a database?

    <p>Data redundancy</p> Signup and view all the answers

    What term describes the recovery management of a database after a failure?

    <p>Backup and recovery management</p> Signup and view all the answers

    What is the significance of durability in ACID properties?

    <p>Ensures changes persist after a transaction completes.</p> Signup and view all the answers

    Which part of a database system includes hardware, software, people, procedures, and data?

    <p>Database system</p> Signup and view all the answers

    What does data integrity help to minimize within a database?

    <p>Data redundancy</p> Signup and view all the answers

    What is described as a high-level understanding of data that abstracts physical storage?

    <p>Semantic data model</p> Signup and view all the answers

    What does the Hierarchical Model create?

    <p>A hierarchical tree with parent/child relationships</p> Signup and view all the answers

    Which model is represented using graphical representations of database components?

    <p>Entity Relationship Model</p> Signup and view all the answers

    What notation uses a three-pronged symbol to represent the 'many' side of a relationship?

    <p>Crow's Foot Notation</p> Signup and view all the answers

    In UML Class Diagrams, which symbol denotes private attributes or operations?

    <p>Minus (-)</p> Signup and view all the answers

    What type of relationship in class diagrams indicates a 'part of' connection?

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

    Which schema operates at the lowest level, describing data storage methods?

    <p>Physical Schema</p> Signup and view all the answers

    What is the process called for evaluating and correcting table structures to minimize redundancies?

    <p>Data Normalization</p> Signup and view all the answers

    What class relationship is displayed as a solid line with a hollow arrowhead from the child to the parent?

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

    Study Notes

    Database Systems

    • The first general purpose DBMS was designed by Charles William Bachman III at General Electric
    • The DBMS, called Information Management System (IMS), formed the basis for an alternative data representation framework called the hierarchical data model
    • Data is defined as raw facts
    • Data management is a discipline that focuses on the proper generation, storage, and retrieval of data
    • End-user data is defined as raw facts of interest to the end-user
    • Metadata is data about data and helps integrate and manage end-user data
    • A workgroup database is a multiuser database that supports a relatively small number of users (usually fewer than 50) or a specific department within an organization
    • An enterprise database is used by the entire organization and supports many users (more than 50, usually hundreds) across many departments
    • A centralized database supports data located at a single site
    • Bitcoin is an example of a decentralized database system
    • A field is a character or group of characters (alphabetic or numeric) that has a specific meaning and is used to define and store data
    • A record is a logically connected set of one or more fields that describes a person, place, or thing
    • A file is a collection of related records
    • Atomicity is a property of a database transaction; it ensures that the transaction either completes entirely or fails entirely
    • Data redundancy exists when the same data is stored unnecessarily at different places
    • Data anomaly develops when not all of the required changes in the redundant data are made successfully
    • Isolation means that the execution of all transactions should be isolated from other transactions
    • Durability ensures that the changes made during a transaction should exist after completion of the transaction

    Database Systems Components

    • The five major components of a database system are hardware, software, people, data, and procedures
    • DBMS software manages the database within the database system
    • Data optimization relates to the activities that make the database perform more efficiently in terms of storage and access speed
    • Data transformation and presentation is the function of DBMS that transforms entered data to conform to the required data structures
    • Data integrity promotes and enforces integrity rules, thus minimizing data redundancy and maximizing data consistency
    • Back-up and recovery management is the function of DBMS wherein a failed database can be recovered
    • A schema is a description of data in terms of a data model
    • There is only a single conceptual view of a single database

    Database Design

    • The ER diagram was first introduced in 1976
    • NoSQL is a 4th generation data model
    • An attribute is a characteristic of an entity
    • A business rule is a brief, precise, and unambiguous description of a policy, procedure, or principle within an organization
    • File system is the 1st Generation of Data Model
    • Object-oriented/object-relational is the 4th Generation of Data Model

    Relational Databases and NoSQL

    • SQL engine executes all queries or data requests
    • NoSQL models use schema-free or semi-structured approaches

    Hierarchical, Network, and Relational Data Models

    • The hierarchical data model is a model whose basic logical structure is represented by an upside-down tree
    • The hierarchical model depicts a set of one-to-many (1M) relationships between a parent and its children segments
    • The network model allows a record to have more than one parent
    • Data Definition Language (DDL) enables the administrator to define the schema components
    • The hierarchical model creates a hierarchical tree with a parent/child relationship, whereas the network model has graphs and links

    Entity-Relationship Modeling

    • The Entity relationship model uses graphical representations to model database components
    • Relationships describe associations among data
    • Crows foot notation is derived from the three-pronged symbol used to represent the "many" side of the relationship
    • Chen's notation uses connections written next to each entity box, and relationships are represented by a diamond connected to the related entities through a relationship line
    • Dependent entities rely upon the existence of other entities

    UML Class Diagram

    • UML class diagrams are used to represent data and their relationships within the larger UML object-oriented system's modeling language
    • A class diagram is also known as a structural diagram
    • The minus symbol (-) denotes private attributes or operations
    • The hash symbol (#) denotes protected attributes or operations
    • A conceptual model represents the concepts in the domain
    • Specification focuses on the interfaces of Abstract Data Type (ADT) in the software
    • Inheritance is a class relationship displayed as a solid line with a hollow arrowhead that points from the child element to the parent element
    • Aggregation is a special type of association that represents a "part of” relationship
    • Composition is a special type of aggregation where parts are destroyed when the whole is destroyed
    • Dependency is a class relationship wherein an object of one class might use an object of another class in the code of a method
    • Realization is a class relationship between the blueprint class and the object containing its respective implementation level details
    • The physical schema describes the way data are saved on storage media such as disks or tapes
    • Data normalization is a process for evaluating and correcting table structures to minimize data redundancies, thereby reducing the likelihood of data anomalies

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    DBMS_REVIEWER_2-5-1 (1).pdf

    Description

    Explore the essential concepts of Database Management Systems (DBMS) in this quiz. Learn about different types of databases, data definitions, and the importance of metadata. Test your knowledge on centralized and decentralized database systems.

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