Part I: Overview of Data Modeling |
|
1 | (194) |
|
|
3 | (32) |
|
|
3 | (1) |
|
A Data-Centered Perspective |
|
|
3 | (1) |
|
|
4 | (2) |
|
Design, Choice, and Creativity |
|
|
6 | (2) |
|
Why Is the Data Model so Important? |
|
|
8 | (3) |
|
|
8 | (2) |
|
|
10 | (1) |
|
|
10 | (1) |
|
|
11 | (4) |
|
|
11 | (1) |
|
|
11 | (1) |
|
Enforcement of Business Rules |
|
|
11 | (1) |
|
|
12 | (1) |
|
Stability and Flexibility |
|
|
12 | (2) |
|
|
14 | (1) |
|
Communication Effectiveness |
|
|
15 | (1) |
|
|
15 | (1) |
|
Performance and Implementation Issues |
|
|
16 | (6) |
|
Logical and Physical Database Designs |
|
|
16 | (4) |
|
Modifying the Data Model to Improve Performance |
|
|
20 | (1) |
|
Roles of Data Modeler and Physical Database Designer |
|
|
20 | (1) |
|
When Performance Is Paramount |
|
|
21 | (1) |
|
Where Does the Data Model Fit In? |
|
|
22 | (4) |
|
Function-Driven Approaches |
|
|
22 | (1) |
|
|
23 | (1) |
|
Data-Driven versus Function-Driven |
|
|
24 | (1) |
|
Object-Oriented Approaches |
|
|
24 | (1) |
|
|
25 | (1) |
|
Who Should Be Involved in Data Modeling? |
|
|
26 | (1) |
|
Costs and Benefits of Data Modeling |
|
|
27 | (1) |
|
Is Data Modeling Still Relevant? |
|
|
28 | (2) |
|
Terminology - ``Data Model'' |
|
|
30 | (1) |
|
Alternative Approaches to Data Modeling |
|
|
31 | (1) |
|
|
31 | (2) |
|
|
33 | (2) |
|
|
35 | (32) |
|
An Informal Example of Normalization |
|
|
35 | (4) |
|
|
39 | (1) |
|
|
40 | (2) |
|
|
42 | (3) |
|
|
42 | (1) |
|
|
43 | (1) |
|
|
43 | (1) |
|
|
44 | (1) |
|
Repeating Groups and First Normal Form |
|
|
45 | (5) |
|
Limit on Maximum Number of Occurrences |
|
|
45 | (1) |
|
Data Reusability and Program Complexity |
|
|
46 | (1) |
|
Recognizing Repeating Groups |
|
|
46 | (1) |
|
Removing Repeating Groups |
|
|
47 | (1) |
|
Determining the Key of the New Table |
|
|
48 | (1) |
|
|
49 | (1) |
|
Second and Third Normal Forms |
|
|
50 | (7) |
|
Problems with Tables in First Normal Form |
|
|
50 | (1) |
|
|
50 | (1) |
|
|
51 | (3) |
|
|
54 | (3) |
|
Definitions and a Few Refinements |
|
|
57 | (5) |
|
Determinants and Functional Dependency |
|
|
57 | (1) |
|
|
57 | (1) |
|
|
57 | (1) |
|
A Formal Definition of Third Normal Form |
|
|
58 | (1) |
|
|
59 | (1) |
|
|
60 | (1) |
|
Denormalization and Unnormalization |
|
|
60 | (2) |
|
Choice, Creativity, and Normalization |
|
|
62 | (4) |
|
|
66 | (1) |
|
|
66 | (1) |
|
The Entity-Relationship Approach |
|
|
67 | (44) |
|
|
67 | (1) |
|
A Diagrammatic Representation |
|
|
68 | (8) |
|
|
69 | (1) |
|
Diagrammatic Representation of Foreign Keys |
|
|
70 | (1) |
|
|
70 | (1) |
|
|
71 | (1) |
|
|
72 | (2) |
|
|
74 | (2) |
|
The Top-Down Approach: Entity-Relationship Modeling |
|
|
76 | (3) |
|
Developing the Diagram Top Down |
|
|
77 | (1) |
|
|
78 | (1) |
|
|
79 | (7) |
|
Entity Diagramming Convention |
|
|
80 | (1) |
|
|
81 | (1) |
|
|
82 | (4) |
|
|
86 | (18) |
|
Relationships Diagramming Conventions |
|
|
86 | (5) |
|
Many-to-Many Relationships |
|
|
91 | (6) |
|
|
97 | (1) |
|
Self-Referencing Relationships |
|
|
98 | (3) |
|
Relationships of Higher Degree |
|
|
101 | (1) |
|
|
102 | (2) |
|
|
104 | (1) |
|
Using UML Object Class Diagrams |
|
|
105 | (1) |
|
Creativity and E-R Modeling |
|
|
106 | (3) |
|
|
109 | (2) |
|
|
111 | (38) |
|
|
111 | (1) |
|
Different Levels of Generalization |
|
|
111 | (3) |
|
|
114 | (2) |
|
Representation of Subtypes and Supertypes |
|
|
116 | (2) |
|
Subtypes and Supertypes as Entities |
|
|
118 | (1) |
|
|
119 | (1) |
|
|
120 | (1) |
|
Attributes and Primary Keys of Supertypes and Subtypes |
|
|
121 | (1) |
|
Conversion to a Relational Model |
|
|
122 | (7) |
|
Implementation at a Single Level of Generalization |
|
|
122 | (2) |
|
Implementation at Multiple Levels of Generalization |
|
|
124 | (1) |
|
|
125 | (1) |
|
What Happens to Relationships? |
|
|
126 | (3) |
|
Nonoverlapping and Exhaustive |
|
|
129 | (2) |
|
Overlapping Subtypes and Roles |
|
|
131 | (2) |
|
Ignoring Real World Overlaps |
|
|
131 | (1) |
|
Modeling Only the Supertype |
|
|
132 | (1) |
|
Modeling the Roles as Participation in Relationships |
|
|
132 | (1) |
|
Using Role Entities and One-to-One Relationships |
|
|
133 | (4) |
|
|
134 | (3) |
|
|
137 | (1) |
|
Benefits of Using Subtypes and Supertypes |
|
|
137 | (6) |
|
|
137 | (1) |
|
Presentation - Level of Detail |
|
|
138 | (2) |
|
|
140 | (1) |
|
Classifying Common Patterns |
|
|
141 | (1) |
|
|
142 | (1) |
|
When Do We Stop Supertyping and Subtyping? |
|
|
143 | (4) |
|
|
143 | (1) |
|
Different Attribute Groups |
|
|
144 | (1) |
|
|
144 | (1) |
|
|
145 | (1) |
|
Migration from One Subtype to Another |
|
|
145 | (1) |
|
|
145 | (1) |
|
Capturing Meaning and Rules |
|
|
146 | (1) |
|
|
147 | (1) |
|
|
147 | (1) |
|
|
148 | (1) |
|
|
149 | (26) |
|
|
149 | (2) |
|
Getting Started - Identifying Entities |
|
|
151 | (1) |
|
Patterns and Generic Models |
|
|
152 | (9) |
|
|
152 | (2) |
|
|
154 | (1) |
|
Adapting Generic Models from Other Applications |
|
|
155 | (5) |
|
Developing a Generic Model |
|
|
160 | (1) |
|
When There Isn't a Generic Model |
|
|
161 | (1) |
|
|
161 | (5) |
|
|
166 | (1) |
|
When the Problem is Too Complex |
|
|
167 | (2) |
|
Developing Entity Definitions |
|
|
169 | (1) |
|
|
170 | (1) |
|
|
171 | (3) |
|
|
171 | (1) |
|
|
172 | (1) |
|
|
172 | (1) |
|
|
173 | (1) |
|
|
173 | (1) |
|
Being Understanding and Understood |
|
|
174 | (1) |
|
|
174 | (1) |
|
Organizing the Data Modeling Task |
|
|
175 | (20) |
|
Data Modeling in the Real World |
|
|
175 | (1) |
|
Roles and Responsibilities |
|
|
176 | (2) |
|
|
178 | (2) |
|
Inputs to the Modeling Task |
|
|
180 | (9) |
|
|
180 | (4) |
|
Existing Systems and Reverse Engineering |
|
|
184 | (2) |
|
|
186 | (3) |
|
|
189 | (3) |
|
Comparison with the Function Model |
|
|
189 | (1) |
|
|
190 | (1) |
|
|
191 | (1) |
|
|
191 | (1) |
|
|
192 | (1) |
|
|
193 | (1) |
|
|
194 | (1) |
Part II: Advanced Data Modeling |
|
195 | (242) |
|
More About Relationships and Foreign Keys |
|
|
197 | (40) |
|
|
197 | (1) |
|
Translating Relationships into Foreign Keys |
|
|
198 | (9) |
|
|
198 | (1) |
|
|
199 | (2) |
|
|
201 | (2) |
|
|
203 | (4) |
|
|
207 | (1) |
|
|
208 | (4) |
|
The Concept of Transferability |
|
|
209 | (1) |
|
The Importance of Transferability |
|
|
210 | (1) |
|
Documenting Transferability |
|
|
210 | (2) |
|
|
212 | (7) |
|
One-to-One Relationships and Creativity |
|
|
212 | (2) |
|
When to Use One-to-One Relationships |
|
|
214 | (4) |
|
Implementing One-to-One Relationships |
|
|
218 | (1) |
|
Self-Referencing Relationships |
|
|
219 | (8) |
|
Hierarchies (One-to-Many Relationships) |
|
|
219 | (3) |
|
Networks (Many-to-Many Relationships) |
|
|
222 | (3) |
|
Chains (One-to-One Relationships) |
|
|
225 | (2) |
|
Relationships Involving Three or More Entities |
|
|
227 | (1) |
|
Generalization of Relationships |
|
|
227 | (6) |
|
Generalizing Multiple One-to-Many Relationships to a Single Many-to-Many Relationship |
|
|
231 | (1) |
|
Generalizing Multiple One-to-Many Relationships to a Single One-to-Many Relationship |
|
|
232 | (1) |
|
|
233 | (2) |
|
Entities without Relationships |
|
|
233 | (1) |
|
Allowed Combinations of Cardinality and Optionality |
|
|
234 | (1) |
|
|
235 | (2) |
|
|
237 | (30) |
|
|
237 | (1) |
|
Introduction to the Higher Normal Forms |
|
|
238 | (1) |
|
|
238 | (1) |
|
|
239 | (6) |
|
Example of Structure in 3NF but Not in BCNF |
|
|
239 | (3) |
|
|
242 | (1) |
|
Enforcement of Rules Versus BCNF |
|
|
243 | (1) |
|
A Note on Domain Key Normal Form |
|
|
244 | (1) |
|
Fourth Normal Form (4NF) and Fifth Normal Form (5NF) |
|
|
245 | (11) |
|
Data in BCNF but Not in 4NF |
|
|
245 | (3) |
|
|
248 | (4) |
|
Recognizing 4NF and 5NF Situations |
|
|
252 | (3) |
|
Checking for 4NF and 5NF with the Business Specialist |
|
|
255 | (1) |
|
Further Reading on Higher Normal Forms |
|
|
255 | (1) |
|
Beyond 5NF - Splitting Tables Based on Candidate Keys |
|
|
256 | (1) |
|
Other Normalization Issues |
|
|
257 | (8) |
|
Normalization and Redundancy |
|
|
257 | (2) |
|
Look-Up Tables Produced by Normalization |
|
|
259 | (4) |
|
Selecting the Primary Key after Removing Repeating Groups |
|
|
263 | (1) |
|
Sequence of Normalization and Cross-Table Anomalies |
|
|
264 | (1) |
|
Advanced Normalization in Perspective |
|
|
265 | (1) |
|
|
266 | (1) |
|
Primary Keys and Identity |
|
|
267 | (24) |
|
Basic Requirements and Trade-Offs |
|
|
267 | (2) |
|
|
269 | (2) |
|
|
269 | (1) |
|
Data Unavailable at Time of Entry |
|
|
270 | (1) |
|
|
270 | (1) |
|
|
271 | (1) |
|
|
272 | (1) |
|
|
273 | (2) |
|
Structured Keys and Weak Entities |
|
|
275 | (7) |
|
Problems with Structured Keys |
|
|
275 | (1) |
|
Using Structured Keys to Control Transferability |
|
|
276 | (1) |
|
|
277 | (2) |
|
Programming and Structured Keys |
|
|
279 | (1) |
|
Performance Issues with Structured Keys |
|
|
280 | (2) |
|
|
282 | (4) |
|
When to Use Surrogate Keys |
|
|
282 | (1) |
|
Should Surrogate Keys Be Visible? |
|
|
283 | (1) |
|
Surrogate Keys and Subtypes |
|
|
284 | (1) |
|
|
285 | (1) |
|
Null and Partially-Null Keys |
|
|
286 | (2) |
|
|
288 | (1) |
|
|
288 | (1) |
|
|
288 | (1) |
|
|
289 | (2) |
|
|
291 | (36) |
|
|
291 | (1) |
|
|
292 | (1) |
|
Attribute Disaggregation - One Fact per Attribute |
|
|
293 | (6) |
|
|
295 | (1) |
|
|
296 | (1) |
|
|
297 | (1) |
|
Inappropriate Generalization |
|
|
298 | (1) |
|
Is a Foreign Key an Attribute? |
|
|
299 | (1) |
|
|
300 | (10) |
|
The Attribute Taxonomy in Detail |
|
|
301 | (5) |
|
Attribute Datatype and Length Requirements |
|
|
306 | (3) |
|
Conversion between External and Internal Representations |
|
|
309 | (1) |
|
|
310 | (4) |
|
Objectives of Standardizing Attribute Names |
|
|
310 | (1) |
|
Some Guidelines for Attribute Naming |
|
|
311 | (3) |
|
|
314 | (11) |
|
|
314 | (1) |
|
Attribute Generalization Resulting From Entity Generalization |
|
|
315 | (2) |
|
Attribute Generalization within Entities |
|
|
317 | (6) |
|
Limits to Attribute Generalization |
|
|
323 | (2) |
|
|
325 | (2) |
|
|
327 | (24) |
|
|
327 | (1) |
|
Audit Trails and Snapshots |
|
|
328 | (10) |
|
The Basic Audit Trail Approach |
|
|
329 | (5) |
|
|
334 | (1) |
|
The Basic Snapshot Approach |
|
|
335 | (3) |
|
|
338 | (1) |
|
|
338 | (1) |
|
|
339 | (1) |
|
Modeling Time-Dependent Relationships |
|
|
340 | (7) |
|
One-to-Many Relationships |
|
|
340 | (5) |
|
Many-to-Many Relationships |
|
|
345 | (2) |
|
Self-Referencing Relationships |
|
|
347 | (1) |
|
|
347 | (2) |
|
Changes to the Data Structure |
|
|
347 | (2) |
|
|
349 | (1) |
|
|
350 | (1) |
|
|
351 | (38) |
|
|
351 | (2) |
|
|
353 | (3) |
|
|
353 | (2) |
|
|
355 | (1) |
|
What Rules are Relevant to the Data Modeler? |
|
|
355 | (1) |
|
Discovery and Verification of Business Rules |
|
|
356 | (2) |
|
|
356 | (1) |
|
|
357 | (1) |
|
|
357 | (1) |
|
Documentation of Business Rules |
|
|
358 | (4) |
|
Documentation in an Entity-Relationship Diagram |
|
|
358 | (1) |
|
Documentation in a Relational Model |
|
|
359 | (1) |
|
|
360 | (2) |
|
Use of Subtypes to Document Rules |
|
|
362 | (1) |
|
Implementation of Business Rules |
|
|
362 | (26) |
|
Implementing Particular Rules |
|
|
366 | (5) |
|
Implementation Options: a Detailed Example |
|
|
371 | (4) |
|
Implementing Mandatory Relationships |
|
|
375 | (2) |
|
|
377 | (1) |
|
Restricting an Attribute to a Discrete Set of Values |
|
|
378 | (4) |
|
Rules Involving Multiple Attributes |
|
|
382 | (1) |
|
Recording Data that Supports Rules |
|
|
383 | (3) |
|
Recording Information about Breaking the Rules |
|
|
386 | (1) |
|
Enforcement of Rules through Primary Key Selection |
|
|
387 | (1) |
|
|
388 | (1) |
|
Modeling for Data Warehouses and Data Marts |
|
|
389 | (26) |
|
|
389 | (3) |
|
Characteristics of Data Warehouses and Data Marts |
|
|
392 | (3) |
|
Data Integration - Working with Existing Databases |
|
|
392 | (1) |
|
Loads Rather than Updates |
|
|
393 | (1) |
|
Less Predictable Database ``Hits'' |
|
|
393 | (1) |
|
Complex Queries - Simple Interface |
|
|
394 | (1) |
|
|
394 | (1) |
|
|
394 | (1) |
|
Quality Criteria for Warehouse and Mart Models |
|
|
395 | (3) |
|
|
395 | (1) |
|
|
396 | (1) |
|
Enforcement of Business Rules |
|
|
396 | (1) |
|
|
397 | (1) |
|
Stability and Flexibility |
|
|
397 | (1) |
|
|
397 | (1) |
|
Communication Effectiveness |
|
|
398 | (1) |
|
|
398 | (1) |
|
The Basic Design Principle |
|
|
398 | (1) |
|
Modeling for the Data Warehouse |
|
|
399 | (4) |
|
|
400 | (1) |
|
Understanding Existing Data |
|
|
400 | (1) |
|
|
401 | (1) |
|
Determining Sources and Dealing with Differences |
|
|
401 | (1) |
|
Shaping Data for Data Marts |
|
|
402 | (1) |
|
Modeling for the Data Mart |
|
|
403 | (11) |
|
|
403 | (1) |
|
Multidimensional Databases, Stars and Snowflakes |
|
|
404 | (7) |
|
Modeling Time-Dependent Data |
|
|
411 | (3) |
|
|
414 | (1) |
|
|
415 | (22) |
|
|
415 | (1) |
|
|
416 | (3) |
|
Problems of Data Mismanagement |
|
|
416 | (2) |
|
Managing Data as a Shared Resource |
|
|
418 | (1) |
|
Classification of Existing Data |
|
|
419 | (1) |
|
|
420 | (2) |
|
A Context for Specifying New Databases |
|
|
422 | (2) |
|
Determining Scope and Interfaces |
|
|
422 | (1) |
|
Incorporating the Corporate Data Model in the Development Lifecycle |
|
|
422 | (2) |
|
Guidance for Database Design |
|
|
424 | (1) |
|
Input to Business Planning |
|
|
425 | (1) |
|
Specification of a Corporate Database |
|
|
426 | (2) |
|
Characteristics of Corporate Data Models |
|
|
428 | (1) |
|
Developing a Corporate Data Model |
|
|
429 | (4) |
|
|
429 | (1) |
|
|
430 | (1) |
|
|
431 | (1) |
|
|
432 | (1) |
|
|
433 | (1) |
|
Choice, Creativity, and Corporate Data Models |
|
|
433 | (2) |
|
|
435 | (2) |
Appendices |
|
437 | (14) |
|
Appendix A: Check List for Data Model Review |
|
|
439 | (6) |
|
|
439 | (1) |
|
|
440 | (1) |
|
|
441 | (1) |
|
|
442 | (1) |
|
|
443 | (1) |
|
|
443 | (1) |
|
|
444 | (1) |
|
Appendix B: An Approach to Presenting Large Data Models |
|
|
445 | (6) |
|
Step 1: Partition Data Model into Subject Areas |
|
|
445 | (1) |
|
Step 2: Produce Context Data Model |
|
|
446 | (1) |
|
Step 3: Produce Subject Area Data Models |
|
|
447 | (4) |
Index |
|
451 | |