Time and Relational Theory

Description

Front Cover Time and Relational Theory Copyright Dedication About the Authors Contents Preface Part I: A Review of Relational Concepts Chapter 1: Types and Relations The Running Example Types Relations Exercises Answers Chapter 2: Relational Algebra Rename Restrict Project Union, Intersect, and Minus Join Matching and Not Matching Extend Image Relations Group and Ungroup Extend bis Relational Comparisons Formulating Expressions One Step at a Time Relational Completeness Exercises Answers Chapter 3: Relation Variables Relations vs. Relvars Relational Assignment Keys Foreign Keys Database Constraints Views The Relational Model Exercises Answers Part II: Laying the Foundations Chapter 4: Time and the Database Temporal Databases Timestamped Propositions Valid Time vs. Transaction Time Some Fundamental Questions Exercises Answers Chapter 5: What’s the Problem? Revising the Running Example Sample Constraints and Queries Semitemporalizing the Example Fully Temporalizing the Example Exercises Answers Chapter 6: Intervals What’s an Interval? Applications of Intervals Point and Interval Types A More Searching Example Exercises Answers Chapter 7: Interval Operators Notation Interval Comparisons “Set Operators” Queries Concluding Remarks Exercises Answers Chapter 8: The EXPAND and COLLAPSE Operators Preliminary Remarks Expanded Form Collapsed Form Operator Definitions Unary Relations Nullary Relations Exercises Answers Chapter 9: The PACK and UNPACK Operators I: The Single-Attribute Case Preliminary Examples Packed Form Unpacked Form Further Queries Exercises Answers Chapter 10: The PACK and UNPACK Operators II: The Multiattribute Case PACKING and UNPACKING ON no Attributes UNPACKING ON Two or More Attributes PACKING ON Two or More Attributes A Logical Difference Equivalence of Relations Expand and Collapse Revisited Some Remarks On Redundancy A More Complex Example Exercises Answers Chapter 11: Generalizing the Algebraic Operators A Motivating Example Dyadic Operators n-Adic Operators Monadic Operators Relational Comparisons The Underlying Intuition The Regular Operators Revisited Exercises Answers Part III: Building on the Foundations Chapter 12: Database Design I: Structure The Running Example Revisited Since Relvars Only During Relvars Only A New Normal Form “The Moving Point now” Both Since and During Relvars Concluding Remarks Exercises Answers Chapter 13: Database Design II: Keys and Related Constraints Simplifying the Running Example The Redundancy Problem The Circumlocution Problem PACKED ON The Contradiction Problem WHEN / THEN Combining Specifications PACKED ON without WHEN / THEN WHEN / THEN without PACKED ON Neither PACKED ON nor WHEN / THEN Keys Revisited Putting it all Tgether Exercises Answers Chapter 14: Database Design III: General Constraints The Nine Requirements Since Relvars Only During Relvars Only Both Since and During Relvars Syntactic Shorthands Concluding Remarks Exercises Answers Chapter 15: Queries The Twelve Queries Since Relvars Only During Relvars Only Both Since and During Relvars Views Can Help Exercises Answers Chapter 16: Updates Since Relvars Only During Relvars Only I: U_updates During Relvars Only II: Portion Specifications During Relvars Only III: Multiple Assignment Both Since and During Relvars Views Can Help Exercises Answers Chapter 17: Logged Time and Stated Time A Quick Review A Closer Look The Database and the Log Terminology Logged Times Queries Involving Logged Time Exercises Answers Chapter 18: Point and Interval Types Revisited Ordered vs. Ordinal Type Inheritance Point Types Revisited Numeric Point Types Granularity Revisited Interval Types Revisited Concluding Remarks Exercises Answers Part IV: SQL Support Chapter 19: The SQL Standard Periods Database Design Queries Updates System Time Bitemporal Tables Summary and Assessment Exercises Answers Appendixes Appendix A: Cyclic Point Types The Weekday Example Weekday as a Point Type The Corresponding Interval Type Allen’s Operators UNION, INTERSECT, and MINUS PACK and UNPACK Exercises Answers Appendix B: Is Ordinality Necessary? Appendix C: Generalizing PACK and UNPACK Sets of Relations Sets of Sets Sets of Bags Bags: A Digression Other Kinds of Sets Effect on “PACK and UNPACK ON” Appendix D: A Tutorial D Grammar Appendix E: Implementation Considerations PACK and UNPACK A Graphical Representation Algebraic Operators Update Operators A Final Remark Appendix F: References and Bibliography Index