Data Modeling Essentials 2005 phần 3 ppsx
Data Modeling Essentials 2005 phần 3 ppsx
... an automated documentation tool such as a data dictionary, CASE tool, or other modeling tool. 104 ■ Chapter 3 The Entity-Relationship Approach Figure 3. 31 Another use of a customer entity class. include belong ... particular 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. Simsi...
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Data Modeling Essentials 2005 phần 1 ppsx
... 8 Organizing the Data Modeling Task 231 8.1 Data Modeling in the Real World 231 8.2 Key Issues in Project Organization 233 8.2.1 Recognition of Data Modeling 233 8.2.2 Clear Use of the Data Model 234 Contents ■ xiii Simsion-Witt_FM ... Topics 38 9 Chapter 13 Advanced Normalization 39 1 13. 1 Introduction 39 1 13. 2 Introduction to the Higher Normal Forms 39 2 13. 2....
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Data Modeling Essentials 2005 phần 4 ppsx
... 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 ... Page 152 5.4.4 Column Datatype and Length Requirements We now look at the translation of attribute types into column datatypes. If your DBMS does not support UDTs (user-defined datatypes), you shoul...
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Data Modeling Essentials 2005 phần 9 ppsx
... Branch 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/ 93 Christmas 6 12/25/ 93 Figure 14.12 Post ... Date Reason 18 12/21/ 93 Maintenance 1 12/25/ 93 Christmas 63 12/ 23/ 93 Local Holiday 2 12/25/ 93 Christmas 3 12/25/ 93 Christmas 4 12/25/ 93 Christmas 5 12/25/ 93...
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Data Modeling Essentials 2005 phần 2 potx
... Administration 1, Dose Cost 1, Number of Doses 2, Drug Code 3, Drug Name 3, Manufacturer 3, Method of Administration 3, Dose Cost 3, Number of Doses 3, Drug Code 4, Drug Name 4, Manufacturer 4, Method ... involved if changes to the logical data model are contemplated. In developing a system, data modeling and process modeling usually proceed broadly in parallel. Data model...
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Data Modeling Essentials 2005 phần 5 pot
... Bulwer-Lytton 8.1 Data Modeling in the Real World In the preceding chapters, we have focused largely on learning the lan- guage of data modeling without giving much attention to the practicalities of modeling ... 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 datab...
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Data Modeling Essentials 2005 phần 6 pdf
... redefined, risking inconsistency in the resulting model. You may recall that, in Section 3. 5.8 (Figures 3. 30 and 3. 31), we pre- sented an example in which the cardinality and optionality of two rela- tionships ... Unfortunately, much that is written and taught about data modeling makes this very naive assumption. Experienced data modelers do not try to solicit a data model direc...
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Data Modeling Essentials 2005 phần 7 potx
... combina- tion of < ;Data Item 1 Name>, < ;Data Item 2 Name>, . . . and < ;Data Item n Name>.” 10.18 The Assertions Approach ■ 31 7 Simsion-Witt_10 10/11/04 8:49 PM Page 31 7 10.18.2 .3. Attribute ... maintain data corresponding to that entity class. It is also possible that the data is to be held in some medium other than the relational database: nondatabase files, XML...
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Data Modeling Essentials 2005 phần 8 pps
... unsound) data structure. For a professional data modeler, this should be core knowledge. 13. 3 Boyce-Codd Normal Form 13. 3.1 Example of Structure in 3NF but Not in BCNF Look at the model in Figure 13. 1, ... Malik 1 234 234 5 37 289 J Smith 1 234 Assignment Date 27/2/95 2 /3/ 95 28/2/95 Figure 12.5 Alternative implementations of relationships in an SQL99 DBMS. Simsion-Witt_12 10/11...
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Data Modeling Essentials 2005 phần 10 ppt
... some impact on data modeling. 16.2.1 Data Integration: Working with Existing Databases A data warehouse is not simply a collection of copies of records from source systems. It is a database that ... the data management function. 502 ■ Chapter 17 Enterprise Data Models and Data Management 3 The International Data Managers Association (DAMA) at www.dama.org is a worldwide bod...
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