Data Modeling Essentials 2005 phần 4 ppsx
Data Modeling Essentials 2005 phần 4 ppsx
... the subject b e f o r exclusivity arc Figure 4. 14 Entity class generalization prompted by mutually exclusive relationships. Tax Assessment Taxpayer be for be the subject of Simsion-Witt_ 04 10/8/ 04 7 :40 PM Page 141 The result ... 10/8/ 04 7:56 PM Page 152 5 .4. 4 Column Datatype and Length Requirements We now look at the translation of attribute types into column datatypes. If your...
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Data Modeling Essentials 2005 phần 1 ppsx
... Summary 41 6 Chapter 14 Modeling Business Rules 41 7 14. 1 Introduction 41 7 14. 2 Types of Business Rules 41 8 14. 2.1 Data Rules 41 8 14. 2.2 Process Rules 42 0 xviii ■ Contents Simsion-Witt_FM 12/ 14/ 04 11:32 ... Validation Rules 42 1 14. 3.3 Data Derivation Rules 42 1 14. 4 Documentation of Business Rules 42 2 14. 4.1 Documentation in an E-R Diagram 42 2 14. 4.2...
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Data Modeling Essentials 2005 phần 3 ppsx
... our criterion of elegance is going to be severely tested. 1 14 ■ Chapter 4 Subtypes and Supertypes Simsion-Witt_ 04 10/8/ 04 7 :40 PM Page 1 14 3.5 Relationships ■ 95 Figure 3.22 Resolving a self-referencing ... and Public Company as tables) 126 ■ Chapter 4 Subtypes and Supertypes 5 Including ERwin and ER/Studio. Simsion-Witt_ 04 10/8/ 04 7 :40 PM Page 126 Chapter 4 Subtypes and S...
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Data Modeling Essentials 2005 phần 9 ppsx
... Reason 18 63 1 2 3 4 5 6 12/19/20 04 12/ 24/ 20 04 12/25/20 04 12/25/20 04 12/25/20 04 12/25/20 04 12/25/20 04 12/25/20 04 Maintenance Local Holiday Christmas Christmas Christmas Christmas Christmas Christmas Simsion-Witt_ 14 10/11/ 04 ... 12/25/93 Christmas 4 12/25/93 Christmas 5 12/25/93 Christmas 6 12/25/93 Christmas Figure 14. 11 Subtyping post office closure. Simsion-...
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Data Modeling Essentials 2005 phần 2 potx
... 3, Number of Doses 3, Drug Code 4, Drug Name 4, Manufacturer 4, Method of Administration 4, Dose Cost 4, Number of Doses 4) Simsion-Witt_02 10/11/ 04 8 :47 PM Page 40 practitioners would have had ... the key. For example, we should ask whether more than one 44 ■ Chapter 2 Basics of Sound Structure Simsion-Witt_02 10/11/ 04 8 :47 PM Page 44 2.5 Determining Columns Before we get...
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Data Modeling Essentials 2005 phần 5 pot
... more straightforward handling of reference data until later. As a result, rework may be reduced. 240 ■ Chapter 8 Organizing the Data Modeling Task Simsion-Witt_08 10/8/ 04 7 :46 PM Page 240 retained as subtypes thereof. ... the data model: ■ Add the supertype. ■ Mark each of the original entity classes as a subtype of that supertype. 242 ■ Chapter 8 Organizing the Data Modeli...
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Data Modeling Essentials 2005 phần 6 pdf
... we use for selecting good 276 ■ Chapter 10 Conceptual Data Modeling Simsion-Witt_10 10/11/ 04 8 :49 PM Page 276 Chapter 10 Conceptual Data Modeling “Our job is to give the client not what he wants, ... “top down.” We look at these in the following sections. 2 84 ■ Chapter 10 Conceptual Data Modeling Simsion-Witt_10 10/11/ 04 8 :49 PM Page 2 84 sake of nonredundancy) that each...
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Data Modeling Essentials 2005 phần 7 potx
... <Entity Class 2 Name>.” 3 14 ■ Chapter 10 Conceptual Data Modeling 9 Again these are not alternatives; both assertions must be made. Simsion-Witt_10 10/11/ 04 8 :49 PM Page 3 14 nonnull foreign keys. ... combina- tion of < ;Data Item 1 Name>, < ;Data Item 2 Name>, . . . and < ;Data Item n Name>.” 10.18 The Assertions Approach ■ 317 Simsion-Witt_10 10/11/ 04 8 :...
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Data Modeling Essentials 2005 phần 8 pps
... South Wales 3000 3999 Victoria 40 00 49 99 Queensland 5000 5999 South Australia etc. Figure 13.16 Data derivable across rows. Simsion-Witt_13 10/11/ 04 9: 54 PM Page 41 0 exist in a 5NF structure. ... J Smith 41 260 A Chang 50227 B Malik 135 PRCH Purchasing 163 54 D Sanchez 26732 T Nguyen Employee No Employee Name Assignment Group Project No 50227 B Malik 12 34 2 345 37289 J Smith...
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Data Modeling Essentials 2005 phần 10 ppt
... Sale. 4 Multiple stars in the same data mart can usually share dimension tables. Simsion-Witt_16 10/8/ 04 8:08 PM Page 48 9 data to suit the multidimensional database products that underpin many data ... data management in 49 9 1 A useful starting point is Guidelines to Implementing Data Resource Management, 4th Edition, Data Management Association, 2002. Simsion-Witt_17 10/8...
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