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Database
- Collection of related data organized so it is easy to:
- Access
- Manage
- Update
- Group
- Summarize
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Bit
- Smallest unit of data stored by a computer
- Contains either a 1 or a 0
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Character
- A letter, number, or symbol
- Made of bytes—groups of 8 bits
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Field
- Single unit of relative information
- Has a field name—identifies content
- Content is data type—includes items as Text, Number, Currency, Date/Time
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Record
- Includes a group of related fields
- Contained in tables or data files
- Has a primary key—unique identifier for each record
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Data file (table)
Collection of records
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Database
One or more data files
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Data independence
- Separate from applications
- Changes do not require changes in structure of forms, reports, or programs accessing databases
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Data security
- Prevents contents from being accessed by unauthorized users (e.g., medical records, financial data)
- Audit trail—report of who accesses which data
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Data maintenance
- Required for proper care and protection
- Add records
- Modify records
- Delete records
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Software used to create databases
- File management program: Generates a flat file, meaning that there is no relationship with fields in other files
- Database management systems (DBMSs): Manage multiple tables or files
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File management systems
- Useful for personal and small business needs
- Used to develop a simple computerized system for information storage and retrieval
- Inexpensive and easy to use
- Unable to link to data stored in other files
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DBMS (Database management systems)
- Connects several files or tables
- Manages, accesses, stores, and edits data
- Available in a variety of forms
- Not usually tied to one particular platform
- Able to present information in reports and other formats
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DBMS classifications
- Flat
- Relational
- Object oriented
- Multidimensional
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RDBMS (Relational database management systems)
- Most widely used class of DBMS
- Primary key field used as index to locate records
- Queries can be done through SQL
- Data dictionary lists all tables in database
- Compared to file management program
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ODBMS (Object-oriented database management
systems)
- Suits media applications
- Data represented as objects
- Incorporate sound, video, text, and graphics
- Well suited for applications
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Multidimensional databases
- Depicted as a data cube
- Dimensions typically categories (i.e., time, products, sales, customers, budget, and markets)
- Choice for online analytical processing (OLAP)
- MDX query language can access multiple dimensions
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Data warehouses
- Central location capable of storing all corporate information
- Data available for analysis
- Helps executives make decisions
- Use drill-down method (start with summary level and move down) to focus on specific data
- Data marts similar but support a department or division
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Data mining
- Explores and analyzes data
- Determines data patterns helpful for making decisions
- Managers better understand customers and market
- Can help predict future trends
- Variation is Web mining
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Client/server database systems
- Use database server software—responds to remote users’ requests for information
- Use database client software—provides an interface with the user
- Use queries to request information from the database server
- Examples: ATMs and online banking
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Web–database integration
- Taking database information and making it accessible via the Internet
- Google, Yahoo!, Wikipedia
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Cloud computing database
- Contenders
- Amazon SimpleDB
- Google AppEngine Datastore
- Microsoft SQL Data Services
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Information systems
- Integrate:
- People
- Hardware
- Software
- Data
- Procedures
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Functional divisions
Manage core functions of an organization
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Typical functional divisions
- Accounting
- Finance
- Marketing and sales
- Human Resources
- Production/operation
- Information Systems
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Transaction processing systems
- Handle day-to-day accounting needs
- Keeps record of every transaction involving money
- Save money by automating routine recordkeeping
- Batch online processing
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Management information systems
- Provide information needed to make decisions
- Generate predefined reports
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Decision support systems
- Produce reports more specific than management information system reports
- Enable managers to create simulations
- OLAP (online analytical processing)
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Executive information systems
- Help top-level managers make strategic decisions
- Filter critical information to show trends
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Knowledge management systems
Use information from books and experienced individuals to assist decision making
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Expert systems
- Rely on detailed and in-depth knowledge of experts in a specific field
- Use knowledge base to generate answers
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Retail sector
Computers and databases not only used for traditional applications
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Point-of-sale (POS)
- Credit card authorization
- Inventory system
- Check-screening system
- Signature capture system
- Photo checkout system
- Marketing devices
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