PowerPoint PresentationData Modeling Concepts: GeneralizationGeneralization HierarchyStrategic Data ModelingData Modeling During Systems AnalysisSlide 6Data Modeling StepsData Modeling DiscoverySlide 9EntitiesEntity Discovery for SoundStageThe Context Data ModelThe Key-based Data ModelThe Key-based Data Model With GeneralizationThe Fully-Attributed Data ModelData Analysis & NormalizationNormalization: 1NF, 2NF, 3NFFirst Normal Form ExampleNormalization: 2NFSecond Normal Form ExampleSlide 21Slide 22Third Normal Form ExampleSlide 24SoundStage 3NF Data ModelData-to-Location-CRUD MatrixSlide 27Irwin/McGraw-HillCopyright © 2000 The McGraw-Hill Companies. All Rights reservedWhitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS 5th EditionC H A P T E R7DATA MODELING AND ANALYSIS – Part IIIrwin/McGraw-HillCopyright © 2000 The McGraw-Hill Companies. All Rights reservedWhitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS 5th EditionData Modeling Concepts: Generalization•Generalization –attributes that are common to several types of an entities–grouped into their own entity, called a supertype.•Supertype–an entity whose instances store attributes that are common to one or more entity subtypes. •Subtype – an entity whose instances inherit some common attributes from an entity supertype – then add other attributes that are unique to an instance of the subtype.Irwin/McGraw-HillCopyright © 2000 The McGraw-Hill Companies. All Rights reservedWhitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS 5th EditionGeneralization HierarchyIrwin/McGraw-HillCopyright © 2000 The McGraw-Hill Companies. All Rights reservedWhitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS 5th EditionStrategic Data Modeling•Enterprise Data Model–Fundamental Entities–Relationship may or may not be defined–Provides a starting point for Systems AnalysisIrwin/McGraw-HillCopyright © 2000 The McGraw-Hill Companies. All Rights reservedWhitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS 5th EditionData Modeling During Systems Analysis•Application Data Model – a specific IS•Preliminary Analysis–Simple lists of entities –Examination of Enterprise Data Models•Problem Analysis–Rarely Used–Process models used most often–Data Models in form of Context Models – Advantages•Business Vocabulary•Faster to build•Avoids analysis paralysis•More similar to new system – ie.. ReuseIrwin/McGraw-HillCopyright © 2000 The McGraw-Hill Companies. All Rights reservedWhitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS 5th EditionData Modeling During Systems Analysis•Requirements Analysis–Keystone activity–Steps•Context model•Key-based model•Fully attributed model•Normalized model•Decision Analysis–Aids in implementation decisions•Systems Design–Convert to physical models–Database schemaIrwin/McGraw-HillCopyright © 2000 The McGraw-Hill Companies. All Rights reservedWhitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS 5th EditionData Modeling Steps•Context Model–Entities–Relationships•Key-based Model–Establishes primary keys–Eliminates Non-specifics relationships (n:n)–Precise cardinalities–Generalization hierarchies•Fully attributed model–Remaining descriptive attributes–Subsetting criteria•Normalized model–Removes redundancies–Eliminates inconsistencies–Provides FlexibilityIrwin/McGraw-HillCopyright © 2000 The McGraw-Hill Companies. All Rights reservedWhitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS 5th EditionData Modeling Discovery•Fact Finding–Sampling–JRP–Surveys–InterviewsIrwin/McGraw-HillCopyright © 2000 The McGraw-Hill Companies. All Rights reservedWhitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS 5th EditionData Modeling DiscoverySteps–Discover entities•What are the subjects of the business?–Discover entity keys•How are they uniquely identified?–Discover subsetting criteria•What characteristics divides all instances into useful subsets?–Discover attributes and domains•What are the other descriptive characteristics?, Type?, Values?–Discover security and control requirements•Who can Create, Read, Update or Delete? (CRUD)–Discover Data Timing needs•When?, How long?, Trends?–Discover Generalization hierarchies•Are all instances the same? Can any consolidation be performed?–Discover Relationships and degrees•What events occur that imply relationships? Is more than one entity involved?–Discover Cardinalities•Can event occur with some entities or all?Irwin/McGraw-HillCopyright © 2000 The McGraw-Hill Companies. All Rights reservedWhitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS 5th EditionEntities•Name with a singular noun–Descriptive–Use adjectives to qualify•CUSTOMER ORDER•STOCK ORDER–Define each entity in business termsIrwin/McGraw-HillCopyright © 2000 The McGraw-Hill Companies. All Rights reservedWhitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS 5th Edition Entity Name Business Definitionagreement A contract whereby a member agrees to purchase a certain number of products within a certain time. After fulfilling that agreement, the member becomes eligible for bonus credits that are redeemable for free or discounted products.member An active member of one or more clubs.Note: A target system objective is to re-enroll inactive members as opposed to deleting them.member order An order generated for a member as part of a monthly promotion, or an order initiated by a member.Note: The current system only supports orders generated from promotions; however, customer initiated orders have been given a high priority as an added option in the proposed system.transaction A business event to which the Member Services System must respond.product An inventoried product available for promotion and sale to members.Note: System improvement objectives include (1) compatibility with new bar code system being developed for the warehouse, and (2) adaptability to a rapidly changing mix of products.promotion A monthly or quarterly event whereby special product offerings are made available to members. Entity Discovery for SoundStageIrwin/McGraw-HillCopyright © 2000 The McGraw-Hill Companies. All Rights reservedWhitten Bentley DittmanSYSTEMS ANALYSIS AND DESIGN METHODS 5th EditionThe Context Data ModelMEMBER ORDERMEMBERTRANSACTIONPRODUCTAGREEMENTPROMOTIONresponds