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Database Management Required Reading for ITEC 3365

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Title: Database Management Required Reading for ITEC 3365


1
Database Management Required Reading for ITEC
3365
  • Bret Detillier Michael L. Gibson
  • Department of Information Logistics Technology
  • University of Houston

2
Database
  • A collection of integrated data created by a
    person known as a database administrator (DBA)
    who uses a software system known as a database
    management system (DBMS) to create the database.
  • Databases maintain large-scale accumulations of
    integrated data shared by persons with varying
    perspectives within the firm.

3
Database Data
  • The data contained in a database includes an
    accumulation of most of the facts about data
    types that depict conditions facing the firm
    required to understand the many different areas
    in the firm.
  • Individual data items for data types typically
    reside in a single storage location within disk
    storage provided for the database to serve
    different personnel in the firm.

4
Storing Data Items in Single Locations in the
Database Helps
  • Eliminate redundancy in data and effort.
  • Retain the integrity of the stored data.

5
Data Integrity
  • Refers to the accuracy with which the data items
    and relationships portray their counterpart in
    the business environment.

6
DATABASE
  • A collection of integrated data items that
    includes a description of the data therein, with
    names assigned and descriptions supplied to make
    those data items and collections of data items
    referable.

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Database Creation Using Logical Objects
  • The DBA uses the logical objects of the business,
    as defined in logical data structures (LDSs)
    while creating E/RDs, to create a database in
    correct format and relatively free from errors.

9
Data Integration
  • Refers to the ability to consolidate data items
    from different database files to reconstruct
    logical objects from database objects as either
    input or output to the IS or an online user
    inquiry.
  • The DBMS establishes data integration by how it
    "defines" the database in relation to the
    database's logical database structure, as
    perceived by users, and the physical database
    structure that defines how data is physically
    stored in the database.

10
Internal Database Structure Used to Combine Data
Items
  • Combining relevant data items to describe a data
    type is made possible through the internal
    logical structure of how the DBA directs the DBMS
    to build the database.
  • The internal structure of the database provides
    for data integration to make it possible to
    readily combine separately stored but logically
    related data for specific purposes.

11
Embedded Description Within the Database
  • A database contains a description of itself that
    is used to store, retrieve, and integrate data
    items stored in different physical locations.
  • The embedded description (physical view)
    indicates physical storage locations of data
    items used to retrieve the integrated data items
    (logical view) as defined by the schema.

12
The Database Schema
  • A description of the complete structure (logical
    and physical) of the database, including names
    and descriptions of all data items, sets of data,
    and collections of the data item sets.

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DBA Creation ofthe Database Schema
  • The DBA directs the DBMS to define the database
    schema by assigning names to database files and
    data items in relation to the database design
    that best complies with the user requirements for
    organization data objects.
  • The DBA directs the DBMS to create the schema by
    issuing commands in a command language used to
    communicate with the DBMS.

18
Schema Used to Locate Data Items in the Database
  • The DBMS uses the schema to integrate the logical
    view and physical view of data in the database to
    permit access of data items stored in completely
    different physical locations in such a way that
    the data appears to be physically stored
    together.
  • Programs in systems and online user access
    commands can retrieve logically related data
    items without considering that the data comes
    from completely different physical locations.

19
Query Example
  • QUERY Get the name and address of Mary Smith,
    her doctor's name, her admittance date, and the
    name of her insurance carrier.
  • 1. Access the patient file using "Mary Smith" to
    compare names until Mary Smith's patient file
    is retrieved.
  • 2. Use the PATSSNO (111111112) from Mary Smith's
    patient record to search the admissions file and
    find her admission's record.
  • 3. Use the DRSSNO (222222223) from Mary Smith's
    admissions record to find her doctor's record (A.
    Einstein) in the doctor file.
  • 4. Use the CARRID (101) from Mary Smith's
    admission record to find her record in the
    insurance carrier file.
  • QUERY RESULT Mary Smith 20 Tu Denton TX A.
    Einstein 11/15/84 Prudential.

20
Data Manipulation Commands (DMCs) and Command
Languages
  • The DBMS's communication language also has
    commands called data manipulation commands (DMCs)
    used to cause the DBMS to access appropriate data
    values within the database.
  • Database inquiries require a syntactically
    (grammatically) correct DMC to retrieve the data
    values referenced by designated names within the
    DMC.

21
Online Database Access
  • Users use on-line database access (queries) to
    gain access to information in lieu of what is
    normally supplied to them by the firm's IS, gain
    quicker access to information the IS does supply,
    directly receive reports on data values within
    the database, or perform direct updates when
    unusual sets of events occur within the firm's
    operations.

22
Preprogrammed Database Accesses and Screen Masks
  • IS personnel often create preprogrammed commands
    and/or screen masks to access the database in a
    user friendly method for user issued queries.
  • These preprogrammed accesses are typically
    constructed by creating a program of DMCs.

23
Logical Data Structures from Physical Data
Structures
  • Logical data types illustrated in the
    Enterprise/Methodology Model as logical data
    types (LDSs) typically consist of data items from
    a number of physical data types (PDSs) in the
    database.

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Information
  • Embodies an expansion of knowledge perceived from
    data objects examined in their proper context.

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