The database approach to data management provides significant advantages over the traditional file-based approach Define general data management concepts and terms, highlighting the advantages and disadvantages of the database approach to data management Describe the relational database model and outline its basic features Principles of Information Systems, Seventh Edition

A well-designed and well-managed database is an extremely valuable tool in supporting decision making Identify the common functions performed by all database management systems and identify popular end-user database management systems Principles of Information Systems, Seventh Edition

Identify and briefly discuss current database applications The number and types of database applications will continue to evolve and yield real business benefits Identify and briefly discuss current database applications Principles of Information Systems, Seventh Edition

Introduction Database management system (DBMS): group of programs that manipulate database and provide interface between database and users Database administrator (DBA): a skilled information systems professional who directs all activities related to organization’s database Principles of Information Systems, Seventh Edition

Data Management: The Hierarchy of Data A bit (a binary digit) represents a circuit that is either on or off A byte is typically 8 bits Character: each byte represents a character, the basic building block of information Field: typically a name, number, or combination of characters that describes an aspect of a business object or activity Principles of Information Systems, Seventh Edition

The Hierarchy of Data (continued) Record: a collection of related data fields File: a collection of related records Database: a collection of integrated and related files Hierarchy of data: formed by bits, characters, fields, records, files, and databases Principles of Information Systems, Seventh Edition

Figure 5.1: The Hierarchy of Data Principles of Information Systems, Seventh Edition

Data Entities, Attributes, and Keys Entity: a generalized class of people, places, or things (objects) for which data is collected, stored, and maintained Attribute: a characteristic of an entity Data item: the specific value of an attribute Key: a field or set of fields in a record that is used to identify the record Primary key: a field or set of fields that uniquely identifies the record Principles of Information Systems, Seventh Edition

Figure 5.2: Keys and Attributes Principles of Information Systems, Seventh Edition

The Traditional Approach Versus the Database Approach Traditional approach: separate data files are created and stored for each application program Results in data redundancy: duplication of data in separate files Data redundancy conflicts with data integrity (the degree to which the data in any one file is accurate) Database approach: approach whereby a pool of related data is shared by multiple application programs; offers significant advantages over traditional file-based approach Principles of Information Systems, Seventh Edition

Figure 5.3: The Traditional Approach to Data Management Principles of Information Systems, Seventh Edition

Figure 5.4: The Database Approach to Data Management Principles of Information Systems, Seventh Edition

Table 5.1: Advantages of the Database Approach Principles of Information Systems, Seventh Edition

Table 5.1: Advantages of the Database Approach (continued) Principles of Information Systems, Seventh Edition

Table 5.2: Disadvantages of the Database Approach Principles of Information Systems, Seventh Edition

Data Modeling and the Relational Database Model When building a database, an organization must consider: Content: What data should be collected and at what cost? Access: What data should be provided to which users and when? Logical structure: How should data be arranged so that it makes sense to a given user? Physical organization: Where should data be physically located? Principles of Information Systems, Seventh Edition

Data Modeling Building a database requires two types of designs: Logical design: shows an abstract model of how the data should be structured and arranged to meet an organization’s information needs Physical design: starts from the logical database design and fine-tunes it for performance and cost considerations Principles of Information Systems, Seventh Edition

Data Modeling (continued) Data model: a diagram of data entities and their relationships Entity-relationship (ER) diagrams: data models that use basic graphical symbols to show the organization of and relationships between data Principles of Information Systems, Seventh Edition

Figure 5.5: An Entity-Relationship (ER) Diagram for a Customer Order Database Principles of Information Systems, Seventh Edition

The Relational Database Model Relational model: describes data in which all data elements are placed in two-dimensional tables, called relations, that are the logical equivalent of files In the relational model: Each row of a table represents a data entity Columns of the table represent attributes Domain: the allowable values for data attributes Principles of Information Systems, Seventh Edition

Figure 5.6: A Relational Database Model Principles of Information Systems, Seventh Edition

Manipulating Data Selecting: eliminates rows according to certain criteria Projecting: eliminates columns in a table Joining: combines two or more tables Linking: combines two or more tables using common data attributes to form a new table with only the unique data attributes Principles of Information Systems, Seventh Edition

Database Management Systems (DBMS) A group of programs used as an interface between a database and application programs or a database and user Database types Flat file Single user Multiple users Principles of Information Systems, Seventh Edition

Providing a User View Schema: a description of the entire database User view: the portion of the database a user can access Subschemas are used to create different user views Subschema: a file that contains a description of a subset of the database and identifies which users can view and modify the data items in the subset Principles of Information Systems, Seventh Edition

Figure 5.10: The Use of Schemas and Subschemas Principles of Information Systems, Seventh Edition

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 Principles of Information Systems, Seventh Edition

Figure 5.11: Using a Data Definition Language to Define a Schema Principles of Information Systems, Seventh Edition

Figure 5.12: A Typical Data Dictionary Entry Principles of Information Systems, Seventh Edition

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 Principles of Information Systems, Seventh Edition

Figure 5.13: Logical and Physical Access Paths Principles of Information Systems, Seventh Edition

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 Principles of Information Systems, Seventh Edition

Table 5.6: Examples of SQL Commands Principles of Information Systems, Seventh Edition

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 Principles of Information Systems, Seventh Edition

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 Principles of Information Systems, Seventh Edition

Selecting a Database Management System (continued) Important characteristics of databases to consider (continued): Features of the DBMS Vendor considerations Cost of the system Principles of Information Systems, Seventh Edition

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 Principles of Information Systems, Seventh Edition

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 Principles of Information Systems, Seventh Edition

Figure 5.17: Elements of a Data Warehouse Principles of Information Systems, Seventh Edition

Table 5.8: Common Data-Mining Applications Principles of Information Systems, Seventh Edition

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 Principles of Information Systems, Seventh Edition

Distributed Databases 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 Principles of Information Systems, Seventh Edition

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 Principles of Information Systems, Seventh Edition

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 Principles of Information Systems, Seventh Edition

Figure 5.19: Advantages of ODBC Principles of Information Systems, Seventh Edition

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 Principles of Information Systems, Seventh Edition

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 Principles of Information Systems, Seventh Edition

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, Seventh Edition

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, Seventh Edition

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 Principles of Information Systems, Seventh Edition