Behind The Scenes Databases And Information Systems 6

Technology in Action Chapter 11 Behind the Scenes: Databases and Information Systems

Chapter Topics Files and their uses Databases and their uses Database components Types of databases Database management systems Relational databases Data warehouses and data marts Information systems Data mining

Pros and Cons of Conventional Files Pros Easy to design because of their single-application focus Excellent performance due to optimized organization for a single application Cons Harder to adapt to sharing across applications Harder to adapt to new requirements Need to duplicate attributes in several files.

Files and Tables File – the set of all occurrences of a given record structure. Table – the relational database equivalent of a file. Types of conventional files and tables Master files – Records relatively permanent though values may change Transaction files – Records describe business events Document files – Historical data for review without overhead of regenerating document Archival files – Master and transaction records that have been deleted Table lookup files – Relatively static data that can be shared to maintain consistency Audit files – Special records of updates to other files

Databases Electronic collections of related data Help us organize data Turn data into information

Advantages of Using Databases Store and retrieve large quantities of information Enable information sharing Provide data centralization Promote data integrity Allow for flexible use of data Student housing Financial Aid Recording grades Student Registration Parents Student Information Database

Disadvantages of Using Databases More complex than file technology Somewhat slower performance Investment in DBMS and database experts Need to adhere to design principles to realize benefits Increased vulnerability due to consolidating data in a centralized database

Database Terminology Field Category of information displayed in columns Each field has a field name Field Name

Database Terminology Data types Text Numeric Computational Date Memo Object Hyperlink

Database Terminology Record A group of related fields Record

Database Terminology Table A group of related records Table

Database Terminology Primary key A field value unique to a record Primary Key

Database Types Relational databases Organize data in a table Link tables to each other through their primary keys Object-oriented databases Stores data in objects Handles unstructured data Multidimensional databases Stores data in multiple dimensions Can easily be customized Process data much faster

Database Management Systems (DBMS) Application software designed to capture and analyze data Four main operations of a DBMS are: Creating databases and entering data Viewing and sorting data Extracting data Outputting data

Data Architecture Data architecture – a definition of how: Files and databases are to be developed and used to store data The file and/or database technology to be used The administrative structure set up to manage the data resource Data is stored in some combination of: Conventional files Operational databases – databases that support day-to-day operations and transactions for an information system. Also called transactional databases. Data warehouses – databases that store data extracted from operational databases. To support data mining Personal databases Work group databases

1. Creating Databases and Entering Data Create field names: Identify each type of data Data dictionary

Sample Data Dictionary Report Figure 7-5

Creating Databases and Entering Data (cont) Create individual records: Key-in Import

Data Validation Validation Process of ensuring data entered into the database is correct (or at least reasonable) and complete Validation rules Range check Completeness check Consistency check Alphabetic/numeric checks

2. Viewing and Sorting Data Browse through records Sort records by field name Before sort After sort

3. Extracting or Querying Data Query A question or inquiry Provides records based on criteria Structured query language (SQL) SQL

4. Outputting Data Reports: Printed Summary data reports Export data

Relational Database Operations Relational databases organize data into tables based on logical groupings Relationships are links between tables with related data Common fields between tables need to exist Normalization of data (recording data once) reduces data redundancy

The Relational Data Model Figure 7-6

Administrators Data administrator – a database specialist responsible for data planning, definition, architecture, and management. Database administrator – a specialist responsible for database technology, database design,construction, security, backup and recovery, and performance tuning. A database administrator will administer one or more databases

… To Physical Data Model (Relational Schema)

Data Storage Data warehouses A large scale repository of data Organizes all the data related to an organization Data is organized by subject

Source data Internal sources Company databases, etc. External sources Suppliers, vendors, etc. Customers or Web site visitors Clickstream data Populating Data Warehouses

Data staging Extract data from source Reformat the data Store the data Software programs/procedures created to extract the data and to reformat it for storage Data Staging

Small slices of data Data of a single department Data Marts

Managing Data: Information Systems Information systems Software-based solutions used to gather and analyze information Functions performed by information systems include Acquiring data Processing data into information Storing data Providing output options

Information Systems Categories Office support Transaction processing Management Decision support

Office Support Systems (OSS) Assist employees in day-to-day tasks Improve communications Microsoft Office

Transaction Processing Systems (TPS) Keeps track of everyday business activities Batch processing Real-time processing

Management Information Systems (MIS) Provides timely and accurate information for managers to make business decisions Detail report: Transactions that occur during a period of time Summary report: Consolidate detailed data Exception report: Show unusual conditions

Decision Support Systems (DSS) Help managers develop solutions for specific problems

Data Mining Process by which data are analyzed and investigated Objective is to spot patterns or trends within the data

Data Mining Methods Classification Define data classes Estimation Assign a value to data Affinity grouping or association rules Determine which data goes together Clustering Organize data into subgroups Description and visualization Provides a clear picture of what is happening

Chapter 11 Summary Questions What is a database and why is it beneficial to use databases?

Chapter 11 Summary Questions What components make up a database?

Chapter 11 Summary Questions What types of databases are there?

Chapter 11 Summary Questions What do database management systems do?

Chapter 11 Summary Questions How do relational databases organize and manipulate data?

Chapter 11 Summary Questions What are data warehouses and data marts and how are they used?

Chapter 11 Summary Questions What is an information system and what types of information systems are used in business?

Chapter 11 Summary Questions What is data mining and how does it work?

Behind The Scenes Databases And Information Systems 6

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