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Chapter 5 Lecture 2
Principles of Information Systems 2
Objectives
• Understand Data definition language (DDL) and data dictionary
• Learn about popular DBMSs
• Understand types of Data Warehouses
• Conceptually understand ODBC
Principles of Information Systems 3
Creating and Modifying the Database
• Data definition language (DDL)
• A collection of instructions and commands used to define and describe data and data relationships in a specific database
• Allows the database’s creator to describe the data and the data relationships that are to be contained in the schema and subschemas
• Data dictionary: a detailed description of all the data used in the database
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Figure 5.11: Using a Data Definition Language to Define a Schema
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Figure 5.12: A Typical Data Dictionary Entry
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Storing and Retrieving Data
• When an application program request data from DBMS, the application program follows a logical access path
• When the DBMS goes to a storage device to retrieve the requested data, it follows a path to the physical location (physical access path) where the data is stored
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Figure 5.13: Logical and Physical Access Paths
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Manipulating Data and Generating Reports
• Data manipulation language (DML): the commands that are used to manipulate the data in a database
• Structured Query Language (SQL): adopted by the American National Standards Institute (ANSI) as the standard query language for relational databases
• Once a database has been set up and loaded with data, it can produce reports, documents, and other outputs
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Table 5.6: Examples of SQL Commands
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Popular Database Management Systems
• Popular DBMSs for end users include Microsoft’s Access and Corel’s Paradox
• The complete database management software market includes databases by IBM, Oracle, and Microsoft
• Examples of open-source database systems: PostgreSQL and MySQL
• Many traditional database programs are now available on open-source operating systems
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Selecting a Database Management System
• Important characteristics of databases to consider:
• Size of the database
• Number of concurrent users
• Performance
• The ability of the DBMS to be integrated with other systems
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Selecting a Database Management System (continued)
• Important characteristics of databases to consider (continued):
• Features of the DBMS
• Vendor considerations
• Cost of the system
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Database Applications: Linking the Company Database to the Internet
• Corporate databases can be accessed by customers, suppliers, and company employees through:
• The Internet
• Intranets
• Extranets
• Semantic Web: a seamless integration of traditional databases with the Internet
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Data Warehouses, Data Marts, and Data Mining
• Data warehouse: a database that collects business information from many sources in the enterprise, covering all aspects of the company’s processes, products, and customers
• Data mart: a subset of a data warehouse
• Data mining: an information-analysis tool that involves the automated discovery of patterns and relationships in a data warehouse
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Figure 5.17: Elements of a Data Warehouse
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Table 5.8: Common Data-Mining Applications
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Business Intelligence
• Business intelligence (BI): the process of gathering enough of the right information in a timely manner and usable form and analyzing it to have a positive impact on business strategy, tactics, or operations
• Knowledge management: the process of capturing a company’s collective expertise wherever it resides and distributing it wherever it can help produce the biggest payoff
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Distributed Databases
• Distributed database
• A database in which the data may be spread across several smaller databases connected via telecommunications devices
• Corporations get more flexibility in how databases are organized and used
• Replicated database: a database that holds a duplicate set of frequently used data
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Online Analytical Processing (OLAP)
• Software that allows users to explore data from a number of different perspectives
Table 5.9: Comparison of OLAP and Data Mining
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Open Database Connectivity (ODBC)
• Standards that ensure that software can be used with any ODBC-compliant database
• Can be used to export, import, or link tables between different applications
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Figure 5.19: Advantages of ODBC
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Object-Oriented and Object-Relational Database Management Systems
• Object-oriented database
• Stores both data and its processing instructions
• Method: a procedure or action
• Message: a request to execute or run a method
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Object-Oriented and Object-Relational Database Management Systems
(continued)
• Object-oriented database management system (OODBMS): group of programs that manipulate an object-oriented database and provide a user interface and connections to other application programs
• Object-relational database management system (ORDBMS): DBMS capable of manipulating audio, video, and graphical data
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Summary
• Hierarchy of data: bits, characters, fields, records, files, and databases
• Entity: a generalized class of things (objects) for which data is collected, stored, and maintained
• Attribute: characteristic of an entity
• Data model: diagram of entities and relationships
• Relational model: describes data in which all elements are placed in two-dimensional tables called relations
Principles of Information Systems 25
Summary (continued)
• Selecting: eliminates rows according to certain criteria
• Projecting: eliminates columns in a table
• Database management system (DBMS): group of programs used as an interface
• Between a database and application programs
• Database and the user
• Data dictionary: detailed description of all the data used in the database
Principles of Information Systems 26
Summary (continued)
• Data warehouse: database that collects business information from all aspects of a company’s processes, products, and customers
• Data mining: an information-analysis tool for the automated discovery of patterns and relationships in a data warehouse
• Open database connectivity (ODBC) standards: ensure that software can be used with any ODBC-compliant database