SQL: A Comparative Survey is a companion to Hugh Darwen’s An Introduction to Relational Database Theory, best studied in parallel with that text. Closely following the structure of the theory book, it shows how the examples in that book can be expressed in SQL. SQL’s many deviations from relational database theory are thus exposed and their consequences discussed. Drawing on the author’s long experience as a member of the committee responsible for production of the ISO SQL standard, the book includes copious Historical Notes showing how SQL has evolved from its very beginnings in the 1970s.
Beschreibung
Inhalt
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- Introduction
- Introduction
- “Collection of Variables”
- What Is an SQL Database?
- “Table” Not Equal to “Relation”
- Anatomy of a Table
- What Is a DBMS?
- SQL Is a Database Language
- What Does an SQL DBMS Do?
- Creating and Destroying Base Tables
- Taking Note of Integrity Rules
- Taking Note of Authorisations
- Updating Variables
- Providing Results of Queries
- Values, Types, Variables, Operators
- Introduction
- Anatomy of A Command
- Important Distinctions
- A Closer Look at a Read-Only Operator (+)
- Read-only Operators in SQL
- What Is a Type?
- What Is a Type Used For?
- The Type of a Table
- Table Literals
- Types and Representations
- What Is a Variable?
- Updating a Variable
- Conclusion
- Predicates and Propositions
- Introduction
- What Is a Predicate?
- Substitution and Instantiation
- How a Table Represents an Extension…
- Deriving Predicates from Predicates
- Relational Algebra—The Foundation
- Introduction
- Relations and Predicates
- Relational Operators and Logical Operators
- JOIN and AND
- Renaming Columns
- Projection and Existential Quantification
- Restriction and AND
- Extension and AND
- UNION and OR
- Semidifference and NOT
- Concluding Remarks
- Building on The Foundation
- Introduction
- Semijoin and Composition
- Aggregate Operators
- Tables within a Table
- Using Aggregation on Nested Tables
- Summarization in SQL
- Grouping and Ungrouping in SQL
- Wrapping and unwrapping in SQL
- Table Comparison
- Other Operators on Tables and Rows
- Constraints and Updating
- Introduction
- A Closer Look at Constraints and Consistency
- Expressing Constraint Conditions
- Useful Shorthands for Expressing Some Constraints
- Updating Tables
Great Book
