Temporal data and the relational model : a detailed investigation into the application of interval and relation theory to the problem of temporal database management

Temporal database systems are systems that provide special support for storing, querying, and updating historical and/or future data. Current DBMSs provide essentially no temporal features at all, but this situation is likely to change soon for a variety of reasons; in fact, temporal databases are virtually certain to become important sooner rather than later, in the commercial world as well as in academia. This book provides an in-depth description of the foundations and principles on which those temporal DBMSs will be built. These foundations and principles are firmly rooted in the relational model of data; thus, they represent an evolutionary step, not a revolutionary one, and they will stand the test of time. This book is arranged in three parts and a set of appendixes: * Preliminaries: Provides a detailed review of the relational model, and an overview of the Tutorial D language. * Laying the Foundations: Explains basic temporal data problems and introduces fundamental constructs and operators for addressing those problems. * Building on the Foundations: Applies the material of the previous part to issues of temporal database design, temporal constraints, temporal query and update, and much more. * Appendixes: Include annotated references and bibliography, implementation considerations, and other topics. Key features: * Describes a truly relational approach to the temporal data problem. * Addresses implementation as well as model issues. * Covers recent research on new database design techniques, a new normal form, new relational operators, new update operators, a new approach to the problem of "granularity," support for "cyclic point types," and other matters. * Includes review questions and exercises in every chapter. * Suitable for both reference and tutorial purposes. Front Cover......Page 1 Temporal Data and the Relational Model......Page 4 Copyright Page......Page 6 Contents......Page 12 Preface......Page 18 Part I: Preliminaries......Page 24 1.1 Introduction......Page 26 1.2 The Running Example......Page 27 1.3 Types......Page 29 1.4 Relation Values......Page 34 1.5 Relation Variables......Page 39 1.6 Integrity Constraints......Page 44 1.7 Relational Operators......Page 46 1.8 The Relational Model......Page 57 Exercises......Page 58 2.3_ Introduction......Page 62 2.2 Scalar Type Definitions......Page 64 2.3 Relational Definitions......Page 65 2.4 Relational Expressions......Page 66 2.5 Relational Assignments......Page 70 2.6 Constraint Definitions......Page 71 Exercises......Page 72 Part II: Laying the Foundations......Page 74 3.1 Introduction......Page 76 3.2 Timestamped Propositions......Page 79 3.3 Valid Time versus Transaction Time......Page 82 3.4 Some Fundamental Questions......Page 84 Exercises......Page 87 4.1 Introduction......Page 88 4.2 "Semitemporalizing" Suppliers and Shipments......Page 90 4.3 Fully Temporalizing Suppliers and Shipments......Page 93 Exercises......Page 98 5.1 Introduction......Page 100 5.2 Applications of Intervals......Page 103 5.3 Point Types and Interval Types......Page 104 5.4 A More Searching Example......Page 108 Exercises......Page 109 6.1 Introduction......Page 112 6.2 Comparison Operators......Page 114 6.3 Other Operators......Page 116 6.4 Sample Queries......Page 118 Exercises......Page 120 7.1 Introduction......Page 122 7.2 Expanded Form......Page 123 7.3 Collapsed Form......Page 124 7.4 Operating on Sets of Intervals......Page 126 7.5 Treating Sets as Unary Relations......Page 128 7.6 Operating on Nullary Relations......Page 130 Exercises......Page 131 8.1 Introduction......Page 132 8.2 Packing Relations......Page 134 8.3 Unpacking Relations......Page 138 8.4 Sample Queries......Page 143 8.5 Packing and Unpacking on No Attributes......Page 146 8.6 Packing and Unpacking on Several Attributes......Page 147 8.7 Further Points......Page 154 Exercises......Page 161 9.1 Introduction......Page 164 9.2 Union, Intersect, and Difference......Page 165 9.3 Restrict and Project......Page 170 9.4 Join......Page 172 9.5 Extend and Summarize......Page 173 9.6 Group and Ungroup......Page 174 9.7 Relational Comparisons......Page 178 9.8 The Underlying Intuition......Page 179 9.9 The Regular Relational Operators Revisited......Page 181 Exercises......Page 182 Part III: Building on the Foundations......Page 184 10.1 Introduction......Page 186 10.2 Current Relvars Only......Page 189 10.3 Historical Relvars Only......Page 192 10.4 Sixth Normal Form......Page 195 10.5 "The Moving Point Now"......Page 200 10.6 Both Current and Historical Relvars......Page 203 10.7 Concluding Remarks......Page 206 Exercises......Page 207 11.1 Introduction......Page 210 11.2 The Redundancy Problem......Page 214 11.3 The Circumlocution Problem......Page 215 11.4 The Contradiction Problem......Page 217 11.6 PACKED ON without WHEN/THEN......Page 219 11.7 WHEN/THEN without PACKED ON......Page 220 11.8 Neither PACKED ON nor WHEN/THEN......Page 227 11.9 Candidate Keys Revisited......Page 230 11.10 PACKED ON Revisited......Page 233 Exercises......Page 234 12.1 Introduction......Page 236 12.2 The Nine Requirements......Page 237 12.3 Current Relvars Only......Page 239 12.4 Historical Relvars Only......Page 243 12.5 Both Current and Historical Relvars......Page 250 12.6 Syntactic Shorthands......Page 262 12.7 Concluding Remarks......Page 266 Exercises......Page 267 13.1 Introduction......Page 268 13.2 Current Relvars Only......Page 270 13.3 Historical Relvars Only......Page 275 13.4 Both Current and Historical Relvars......Page 279 13.5 Virtual Relvars Can Help......Page 283 Exercise......Page 288 14.1 Introduction......Page 290 14.2 Current Relvars Only......Page 291 14.3 Historical Relvars Only (1)......Page 294 14.4 Historical Relvars Only (II)......Page 306 14.5 Both Current and Historical Relvars......Page 309 14.6 Virtual Relvars Can Help......Page 315 Exercises......Page 318 15.1 Introduction......Page 320 15.2 A Closer Look......Page 322 15.3 The Database and the Log......Page 325 15.4 Terminology......Page 328 15.5 Logged-Time Relvars......Page 331 15.6 Queries Involving Logged-Time Relvars......Page 334 Exercises......Page 335 16.1 Introduction......Page 336 16.2 Type Inheritance......Page 338 16.3 Point Types Revisited......Page 344 16.4 Further Examples......Page 347 16.5 Granularity Revisited......Page 354 16.6 Interval Types Revisited......Page 358 16.7 Cyclic Point Types......Page 360 16.8 Continuous Point Types......Page 367 Exercises......Page 370 APPENDIXES......Page 372 Appendix A. IMPLEMENTATION CONSIDERATIONS......Page 374 Appendix B. GENERALIZING THE EXPAND AND COLLAPSE OPERATORS......Page 406 Appendix C. REFERENCES AND BIBLIOGRAPHY......Page 414 INDEX......Page 434 ABOUT THE AUTHORS......Page 444