06008_CH02_R cardo.qxd 2/1/11 9:11 AM Page 25 © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC CHAPTERNOT FOR SALE OR DISTRIBUTION NOT FOR2 SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT DatabaseFOR SALE OR DISTRIBUTION Planning NOT FOR SALE OR DISTRIBUTION and Database Architecture © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning,Chapter LLC Objectives NOT FOR SALE ORChapter DISTRIBUTION Objectives NOT FOR SALE OR DISTRIBUTIONIn this chapter you will 2.1 Data as a Resource learn the following: 2.2 Characteristics of Data I The distinction 2.2.1 Data© Jones and Information & Bartlett Learning, LLC © Jonesbetween & dataBartlett and Learning, LLC 2.2.2 LevelsNOT ofFOR Discussing SALE Data OR DISTRIBUTION NOTinformation FOR SALE OR DISTRIBUTION 2.2.3 Data Sublanguages I The four levels of 2.3 Stages in Database Design discussion about data © Jones2.4 Design & Bartlett Tools Learning, LLC © Jones & Bartlett Learning, LLC I NOT FOR2.4.1 SALEData ORDictionary DISTRIBUTION NOT FOR SALE ORThe DISTRIBUTIONsteps in staged 2.4.2 Project Management Software database design 2.5 Database Administration I The functions of a database 2.5.1 Planning and Design administrator © Jones & Bartlett Learning,2.5.2 Developing LLC the Database © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTIONI The distinction 2.5.3 Database Management between DDL and 2.6 The Three-Level Database Architecture DML 2.6.1 External Views I The rationale for 2.6.2 Logical© Jones and &Conceptual Bartlett Models Learning, LLC © Jonesand contents & Bartlett of the Learning, LLC 2.6.3 InternalNOT FOR Model SALE OR DISTRIBUTION NOTthree-level FOR SALE database OR DISTRIBUTION 2.6.4 Data Independence architecture 2.7 Overview of Data Models I The meaning of © Jones2.7.1 & BartlettThe Entity-Relationship Learning, LLC Model © Jones & Bartlettlogical Learning, and physical LLC data independence NOT FOR2.7.2 SALERelational OR DISTRIBUTION Model NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC.© NOTJones FOR SALE & BartlettOR DISTRIBUTION. Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 06008_CH02_R cardo.qxd 2/1/11 9:11 AM Page 26 © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 26 CHAPTER 2 Database Planning and Database Architecture © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC I Characteristics of NOT FOR SALE2.7.3 ORObject-Oriented DISTRIBUTION Model NOT FOR SALE OR DISTRIBUTION various data models 2.7.4 Object-Relational Model 2.7.5 Semistructured Data Model © Jones & Bartlett Learning,2.8 Chapter LLC Summary © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTIONExercises NOT FOR SALE OR DISTRIBUTION On the Companion Website: I Lab Exercises I © Jones & Bartlett Learning, LLC Sample Project© Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION I Student ProjectsNOT FOR SALE OR DISTRIBUTION 2.1 Data as a Resource © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FORIf you SALE were askedOR DISTRIBUTION to identify the resources of a typical businessNOT FOR organiza- SALE OR DISTRIBUTION tion, you would probably include capital equipment, financial assets, and personnel, but you might not think of data as a resource. When a corpo- rate database exists, the data it contains is a genuine corporate resource. © Jones & Bartlett Learning,Since the database LLC contains data about© theJones organization’s & Bartlett operations Learning, LLC NOT FOR SALE OR(called DISTRIBUTION operational data) that is used by NOTmany FORdepartments, SALE andOR since DISTRIBUTION it is professionally managed by a DBA, there is an increased appreciation of the value of the data itself, independent of the applications that use it. A resource is any asset that is of value to an organization and that incurs © Jones & Bartlett Learning, LLCcosts. An organization’s© operational Jones & Bartlettdata clearly Learning, fits this definition. LLC To NOT FOR SALE OR DISTRIBUTIONappreciate the value ofNOT an organization’s FOR SALE data OR more DISTRIBUTION fully, imagine what would happen if the data were lost or fell into the hands of a competitor. Many organizations, such as banks and brokerage houses, are heavily dependent on data, and would fail very quickly if their data were lost. © JonesMost & Bartlettbusinesses Learning, would suffer LLC heavy losses if their operational© Jones data & were Bartlett Learning, LLC NOT FORunavailable. SALE InOR fact, DISTRIBUTION an organization depends on the availabilityNOT FOR of opera- SALE OR DISTRIBUTION tional data in managing its other resources. For example, decisions about the purchase, lease, or use of equipment; financial investments and finan- cial returns; and staffing needs should be made on the basis of informa- © Jones & Bartlett Learning,tion about theLLC organization’s operations.© Jones The recognition & Bartlett of Learning, data as a LLC NOT FOR SALE ORcorporate DISTRIBUTION resource is an important objectiveNOT inFOR developing SALE anOR integrated DISTRIBUTION database environment. The database protects the data resource by provid- ing data security, integrity, and reliability controls through the DBMS. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC.© NOTJones FOR SALE & BartlettOR DISTRIBUTION. Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 06008_CH02_R cardo.qxd 2/1/11 9:11 AM Page 27 © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 2.2 Characteristics of Data 27 © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC 2.2 CharacteristicsNOT FOR SALE of Data OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION In order to appreciate the importance of data as a corporate resource, we need to examine its characteristics more closely. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC 2.2.1 Data and Information NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION We often think of data as information, but these two terms have slightly dif- ferent meanings. The term data refers to the bare facts recorded in the data- base. Information is processed data that is in a form that is useful for making © Jones & Bartlettdecisions. Learning, Information LLC is derived from the stored© Jones data by & re-arranging, Bartlett Learning, select- LLC NOT FOR SALE ORing, DISTRIBUTION combining, summarizing, or performingNOT other FOR operations SALE on OR the DISTRIBUTION data. For example, if we simply print out all the stored items in the database shown in Figure 1.1, without the column headings that identify what they represent, we have data. However, if we print a formatted report such as the one in Fig- ure 1.3, showing© Jones the data & Bartlett in some orderLearning, that helps LLC us make a decision, we © Jones & Bartlett Learning, LLC have information.NOT FOR In practice, SALE most OR people DISTRIBUTION use the two terms interchangeably. NOT FOR SALE OR DISTRIBUTION 2.2.2 Levels of Discussing Data When we discuss data, it is important to distinguish between the real © Jonesworld, & the Bartlett small part Learning, of the real LLC world that the database is concerned© Jones with, & Bartlett Learning, LLC NOT theFOR inherent SALE structure OR DISTRIBUTION of that portion of the world, the structureNOT FOR of the SALE OR DISTRIBUTION database, and the data stored in the database. There are actually four levels of discussion or abstraction to be considered when we talk about databases. We begin with the real world, or reality. On this first level, we talk about © Jones & Bartlettthe Learning, enterprise, LLC the organization for which© the Jones database & Bartlettis designed. Learning, The LLC NOT FOR SALE ORenterprise DISTRIBUTION might be a corporation, governmentNOT agency,FOR SALE university, OR bank,DISTRIBUTION brokerage house, school, hospital, or other organization. As the enterprise functions in the real world, there is too much detail involved to keep track of all the facts needed for decision making by direct observation. Instead, we identify© those Jones facets & of Bartlett the enterprise Learning, that we LLC need to keep track of for © Jones & Bartlett Learning, LLC decision making.NOT FOR The part SALE of the OR real DISTRIBUTION world that will be represented in the NOT FOR SALE OR DISTRIBUTION database is called a miniworld or a universe of discourse. For the mini- world, we begin to develop a conceptual model, which forms the second level of data discussion. We identify entities which are persons, places, © Jonesevents, & objects,Bartlett or Learning,concepts about LLC which we collect data. For© the Jones organiza- & Bartlett Learning, LLC NOT tionsFOR mentioned SALE OR previously, DISTRIBUTION we could choose entities suchNOT as customers, FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC.© NOTJones FOR SALE & BartlettOR DISTRIBUTION. Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 06008_CH02_R cardo.qxd 2/1/11 9:11 AM Page 28 © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 28 CHAPTER 2 Database Planning and Database Architecture