This book presents an overview of the most fundamental aspects of the theory that underlies the Relational Database Model. As such it is self-contained though experience with formal models and abstract data manipulating on the one hand and with the practical use of a relational system on the other hand can help the reader. Such experience will offer the reader a better understanding of and a motivation for the different concepts, theories and results mentioned in the book. We have focussed on the most basic concepts and aspects of the relational model, without trying to give a complete overview of the state of the art of database theory. Recently a lot of books on databases in general and on the relational model in particular have been published. Most of them describe the use of database systems. 'Some clarify how information has to be structured and organized before it can be used to build applications. Others help the user in writing down his applications or in finding tricky ways to optimize the running time or the necessary space. Another category of books treat more fundamental and more general aspects such as the description of the relational model, independent of any implementation, the decomposition in normal forms or the global design of distributed databases. Few, however, are the books that describe in a formal way some of the subjects mentioned above.

Klappentext

The book presents an overview of the most fundamentalaspects of the theory that underlies the Relational DatabaseModel. It provides exact definitions of widely acceptedconcepts, and also covers some recent research topics,making the book very suitable in classes on database theory.

Inhalt
1 Relational Database Model.- 1.1 Relation Schemes.- 1.2 Relation Instances.- 1.3 Database Schemes and Database Instances.- 1.4 Dynamic Schemes and Evolutions.- 1.5 Classification of Constraints.- 1.6 Example.- 1.7 Exercises.- 2 Query Systems.- 2.1 The Relational Algebra.- 2.2 The Tuple Calculus.- 2.3 SQL: Structured Query Language.- 2.4 Reduction of the Tuple Calculus to the Algebra.- 2.5 Reduction of the Algebra to SQL.- 2.6 Reduction of SQL to the Tuple Calculus.- 2.7 Exercises.- 3 Constraints.- 3.1 Some Terminology.- 3.2 Functional Dependencies.- 3.3 Multivalued Dependencies.- 3.4 Join Dependencies.- 3.5 Inclusion Dependencies.- 3.6 Tuple and Equality Generating Dependencies.- 3.7 Exercises.- 4 Vertical Decompositions.- 4.1 First Normal Form.- 4.2 Second and Third Normal Form.- 4.3 Boyce-Codd Normal Form.- 4.4 Constraint Preserving Normalization.- 4.5 Fourth and Fifth Normal Form.- 4.6 Vertical Decomposition and Consistency Checking.- 4.7 Exercises.- 5 Horizontal Decompositions.- 5.1 Horizontal Decompositions.- 5.2 The Membership and Inference Problem for Fds and Ads.- 5.3 The Inheritance of Dependencies.- 5.4 Normal Forms for Horizontal Decompositions.- 5.5 Exercises.- 6 Incomplete Information.- 6.1 Representation Systems for Existing-but-Unknown Nulls.- 6.2 Updating Relations with Existing-but-Unknown Nulls.- 6.3 Constraints in Incomplete Databases.- 6.4 Relations with No-Information Nulls.- 6.5 The Weak Instance Model.- 6.6 Exercises.- 7 The Nested Relational Database Model.- 7.1 Nested Relation Schemes and Instances.- 7.2 The Nested Relational Algebra.- 7.3 Constraints.- 7.4 The Expressiveness of the Nested Relational Algebra.- 7.5 Hierarchical Instances.- 7.6 Exercises.- 8 Updates.- 8.1 Transactions.- 8.2 Equivalent Transactions.- 8.3 Dynamic Relation Constraints.- 8.4 Axiomatization of Equivalence of Transactions.- 8.5 Exercises.