MIS 306 Chapter 11

Physical data model

Logical data is converted into a __________
CASE repository information is expanded to include much more detailed information about specific implementation details
Created to show implementation details and to explain more about the "how" of the final sys

Files

Electronic lists of data that have been optimized to perform a particular transaction

Database

Collection of groupings of information that are related to each other in some way (through common fields)
Logical groupings of information could include categories such as customer data, information about an order, and product information

Database management system (DBMS)

Software that creates and manipulates databases

End-user DBMS

Support small-scale databases that are used to enhance personal productivity
Microsoft Access

Enterprise DBMS

Manages huge volumes of data and support applications that run an entire company
DB2, SQL Server, and Oracle

Data file

Contains an electronic list of information that's formatted for a particular transaction, and the information is changed and manipulated by programs that are written for those purposes

Linked lists

Files with records linked together by the pointers

Master files

Store core information that's important to the business and to the application, such as order information or customer mailing information

Look-up files

Contain static values, such as a list of valid codes or names of US states
Used for validation

Transaction files

Hold information that can be used to update a master file

Audit file

Records "before" and "after" images of data as the data are altered, so that an audit can be performed if the integrity of the data is questioned

History file (archive files)

Stores past transactions (inactive customers, past orders) that are no longer needed by system users
Stored off-line but can be accesses on an as-needed basis

Legacy database

Databases which are based on older technology

Hierarchical database

Use hierarchies, or inverted trees, to represent relationships

Network database

Collections of records that are related to each other through pointers

Relational database

Collections of tables, each of which has a primary key
Most popular database; less efficient, but easier to work with from a development perspective

Primary key

Fields that contain a unique value for each record in the file or table

Foreign key

Primary key field from one table that is repeated in another tables to provide a common field between the two tables

Referential integrity

Ensuring that values linking the tables together through the primary and foreign keys are valid and correctly synchronized

Structure Query Language (SQL)

Standard language for accessing the data in the tables, and it operates on complete tables, as opposed to individual records in the tables
A query written in SQL is applied to all the records in a table all at once

Object (object-oriented) database

Basic premise of object orientation is that all things should be treated as objects that have both data (attributes) and processes (behaviors)

Object-oriented database management systems (OODBMS)

Mainly used to support multimedia applications or systems that involve complex data (graphics, video, and sound)

Data warehousing

The practice of taking data from a company's transaction processing systems, transforming the data, then storing the data for use in the data warehouse that supports business intelligence (BI) systems

Aggregated

Totaled or averaged data

NoSQL databases

Primary common theme is the relational model and SQL are not used
Document-oriented database, wide column stores, and graph databases

Document-oriented database

Manage collections of documents where those documents can have a variety of structures, including large bit files for image, audio, and video data

Wide column stores (extensible record stores)

Store data in records with an ability to hold very large numbers of dynamic columns

Graph databases

Use graph theory to store, map, and query relationships
Essentially a collection of nodes and edges

BigData

Many systems today utilize data collections called ______., that are characterized by high volume, rapid velocity, and great variety

Volume

Data sets are at least a petabyte in size

Velocity

Data is generated rapidly

Variety

Data collection may have structured data, but also may have free-form text, dozens of different formats of Web server and database log files, streams of data about user responses to page content, and possible graphics, audio, and video files

Transaction processing systems

Accept and process many simultaneous reports
Data are continuously updated by a large number of users, and the queries that are asked of the systems typically are predefined or targeted at a small subset of records

BI management information systems (MIS)
BI executive information systems (EIS)
BI expert systems (ES)

Systems built to support decision makers who need to examine large amounts of read-only historical data

Logical entity relationship diagrams (ERDs)

Logical models that depict the "business view" of the data, but omit any implementation details

Physical ERDs

Contains references to exactly how data will be stored in a file or database tables and that much more metadata is added to the CASE repository to describe the data model components

Normalization

Best way to optimize data storage for efficiency

Denormalization

Reduces the number of joins that must be performed in a query, thus speeding up data access
Add redundancy back into the design that is depicted in the physical data model

Look-up tables

Tables that contain descriptions of values

Star schema design

Denormalization data model technique