Data Modeling Essentials 2005 phần 2 potx
Data Modeling Essentials 2005 phần 2 potx
... Arts 1973 0 126 7 Doctor of Philosophy 1976 70964 Bachelor of Arts 1969 22 617 Bachelor of Arts 19 72 226 17 Master of Arts 1977 Employee Number Employee Name Dept. Number 0 126 7 Clark 05 22 617 Walsh ... HO Employee Number Qualification Description Qualification Year 0 126 7 Bachelor of Arts 1970 0 126 7 Master of Arts 1973 0 126 7 Doctor of Philosophy 1976 70964 Bachelor of Arts 1969 2...
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Data Modeling Essentials 2005 phần 7 potx
... will 350 ■ Chapter 11 Logical Database Design Org Unit ID Org Unit Name Parent Org Unit ID 1 Production 1 2 H/R 2 21 Recruitment 2 22 Training 2 221 IT Training 22 22 2 Other Training 22 ORG UNIT (Org Unit ... 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/...
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Data Modeling Essentials 2005 phần 1 ppsx
... Diagrams 22 0 7.4.1 A Conceptual Data Model in UML 22 1 7.4 .2 Advantages of UML 22 2 7.5 Object Role Modeling 22 7 7.6 Summary 22 8 Part II Putting It Together 22 9 Chapter 8 Organizing the Data Modeling ... Data Modeling Task 23 1 8.1 Data Modeling in the Real World 23 1 8 .2 Key Issues in Project Organization 23 3 8 .2. 1 Recognition of Data Modeling 23 3 8...
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Data Modeling Essentials 2005 phần 3 ppsx
... license to be stable 23 98 ■ Chapter 3 The Entity-Relationship Approach 23 The importance of stability for primary keys is discussed in Section 6 .2. 4. Simsion-Witt_03 10/8/04 8: 02 PM Page 98 a single ... conceptual modeling phase, and we touch only lightly on logical modeling issues. We look more closely at these in Chapter 11. 4 .2 Different Levels of Generalization Suppose we a...
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Data Modeling Essentials 2005 phần 4 ppsx
... modified to exclude them. 6 .2. 1 .2 Data Unavailable at Time of Entry All components of a primary key need to be available at the time a row is first stored in the database. This can sometimes ... currency datatype does not accommodate more than two digits after the decimal point, again the decimal datatype should be used. If the decimal datatype is not avail- able, the integer datatype ....
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Data Modeling Essentials 2005 phần 5 pot
... H: Foundation for Future Database Systems: The Third Manifesto, 2nd Edition, Addison-Wesley, 20 00. Simsion-Witt_07 10/8/04 9:19 PM Page 22 4 Chapter 8 Organizing the Data Modeling Task “The fact ... Here is a minimum list. 8 .2. 1 Recognition of Data Modeling Let us repeat what we said in Chapter 1: No database was ever built with- out a data model. Unfortunately, many databases...
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Data Modeling Essentials 2005 phần 6 pdf
... business area and the role of the proposed 25 2 ■ Chapter 9 The Business Requirements Simsion-Witt_09 10/8/04 7:47 PM Page 25 2 28 6 ■ Chapter 10 Conceptual Data Modeling Figure 10.8 Generalizing additional ... same as those we use for selecting good 27 6 ■ Chapter 10 Conceptual Data Modeling Simsion-Witt_10 10/11/04 8:49 PM Page 27 6 Chapter 10 Conceptual Data Modeling “Our...
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Data Modeling Essentials 2005 phần 8 pps
... Purchasing 16354 D Sanchez 26 7 32 T Nguyen Employee No Employee Name Assignment Group Project No 5 022 7 B Malik 123 4 23 45 3 728 9 J Smith 123 4 Assignment Date 27 /2/ 95 2/ 3/95 28 /2/ 95 Figure 12. 5 Alternative ... several 3 92 ■ Chapter 13 Advanced Normalization 1 Date C.J., Darwen H., Lorentzos N, Temporal Data and the Relational Model. Morgan Kaufmann, 20 02. Simsion-Wit...
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Data Modeling Essentials 2005 phần 9 ppsx
... (Branch No, Date, Reason) Branch Date 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 ... No Date 18 12/ 21/93 Maintenance 1 12/ 25/93 63 12/ 23/93 Local Holiday 2 12/ 25/93 3 12/ 25/93 National Closure 4 12/ 25/93 Date Reason 5 12/ 25/93 12/ 25/...
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Data Modeling Essentials 2005 phần 10 ppt
... from conventional operational data- bases. Virtually all of these have some impact on data modeling. 16 .2. 1 Data Integration: Working with Existing Databases A data warehouse is not simply a ... just dimensions. (Figure 16 .2 in Section 16.6 .2 shows an example.) The data modeler is required to fit the data into this 16 .2 Characteristics of Data Warehouses and Data Ma...
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