Database Structures
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Questions and Answers

Which database structure is commonly used for analytical databases that support Online Analytical Processing (OLAP)?

  • Object-Oriented Structure
  • Relational Structure
  • Multidimensional Structure (correct)
  • Hierarchical Structure

    • In a Hierarchical Structure, what type of relationships exist between records?

  • One-to-one
  • One-to-many (correct)
  • Many-to-one
  • Many-to-many

    • What is the primary purpose of the Join operation in Relational Structures?

  • To create a subset of columns in a table
  • To create a subset of records that meet a stated criterion
  • To combine two or more tables temporarily (correct)
  • To sort data in ascending order

    • What is the term for combining data and operations in Object-Oriented Structures?

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

    In Relational Structures, what do rows and columns represent?

    <p>Rows represent records, and columns represent fields</p> Signup and view all the answers

    Which of the following is NOT a characteristic of Multidimensional Structures?

    <p>Popular for online transaction processing</p> Signup and view all the answers

    What is the term for creating a new object by replicating some or all of the characteristics of a parent object in Object-Oriented Structures?

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

    Which database structure is commonly used in some mainframe DBMS packages?

    <p>Network Structure</p> Signup and view all the answers

    What is the primary responsibility of a Database Administrator (DBA)?

    <p>To improve the integrity and security of organizational databases</p> Signup and view all the answers

    What type of information is stored in a data dictionary?

    <p>Data about data (metadata)</p> Signup and view all the answers

    What is the purpose of the data planning process in database development?

    <p>To define the information needs of end users</p> Signup and view all the answers

    What is represented in an entity relationship diagram?

    <p>The data relationships that support a business process</p> Signup and view all the answers

    What is the outcome of the database design process?

    <p>A data model that supports a business process</p> Signup and view all the answers

    What is the purpose of logical design in database development?

    <p>To develop a schema or subschema</p> Signup and view all the answers

    What is the purpose of physical design in database development?

    <p>To determine how data is physically stored and accessed</p> Signup and view all the answers

    What is the relationship between a schema and a subschema?

    <p>A schema is a logical view of the entire enterprise, while a subschema is a logical view for specific end users</p> Signup and view all the answers

    Study Notes

    Database Structures

    • Common database structures include: Hierarchical, Network, Relational, Object-oriented, and Multi-dimensional

    Hierarchical Structure

    • Early DBMS structure
    • Records arranged in a tree-like structure
    • Relationships are one-to-many

    Network Structure

    • Used in some mainframe DBMS packages
    • Many-to-many relationships are possible

    Relational Structure

    • Most widely used structure
    • Data elements are stored in tables
    • Row represents a record; column is a field
    • Can relate data in one file with data in another, if both files share a common data element
    • Relational Operations:
      • Select: create a subset of records that meet a stated criterion
      • Join: combine two or more tables temporarily
      • Project: create a subset of columns in a table

    Multidimensional Structure

    • A multidimensional database is created from multiple relational databases
    • Variation of relational model
    • Uses multidimensional structures to organize data
    • Data elements are viewed as being in cubes
    • Popular for analytical databases that support Online Analytical Processing (OLAP)

    Object-Oriented Structure

    • An object consists of:
      • Data values describing the attributes of an entity
      • Operations that can be performed on the data
    • Encapsulation: combine data and operations
    • Inheritance: new objects can be created by replicating some or all of the characteristics of parent objects
    • Used in object-oriented database management systems (OODBMS)
    • Supports complex data types more efficiently than relational databases (e.g. graphic images, video clips, web pages)

    Evaluation of Database Structures

    • Hierarchical:
      • Works for structured, routine transactions
      • Can’t handle many-to-many relationships
    • Network:
      • More flexible than hierarchical
      • Unable to handle ad hoc requests
    • Relational:
      • Easily responds to ad hoc requests
      • Easier to work with and maintain
      • Not as efficient/quick as hierarchical or network

    Database DevelopmentRoles

    • A Database Administrator (DBA) is in charge of enterprise database development, improving the integrity and security of organizational databases.

    Database Development Tasks

    • Uses Data Definition Language (DDL) to develop and specify data contents, relationships, and structure.
    • Stores data specifications in a data dictionary or a metadata repository.

    Data Dictionary

    • A data dictionary contains data about data (metadata) and relies on specialized software to manage a database of data definitions.
    • It contains information on:
      • Names and descriptions of all types of data records and their interrelationships.
      • End users’ access and use requirements for application programs.
      • Database maintenance.
      • Security.

    Database Development Phases

    Data Planning Process

    • Develop an enterprise model that defines the basic business process of the enterprise.
    • Define the information needs of end users in a business process.
    • Identify key data elements needed to perform specific business activities using entity relationship diagrams.

    Database Design Process

    • Represent data relationships in a data model that supports a business process.
    • This model becomes the schema or subschema for:
      • The physical design of the database.
      • The development of application programs to support business processes.

    Logical Design

    • A schema provides an overall logical view of relationships.
    • A subschema provides a logical view for specific end users.
    • Develop data models for DBMS.

    Physical Design

    • Determine how data will be physically stored and accessed on storage devices.

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    Description

    Quiz about common database structures, including hierarchical, network, relational, object-oriented, and multi-dimensional structures.

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