sql and relational theory how to write accurate sql code

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Sql And Relational Theory

Author : C.J. Date
ISBN : 0596555423
Genre : Computers
File Size : 79. 16 MB
Format : PDF
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Understanding SQL's underlying theory is the best way to guarantee that your SQL code is correct and your database schema is robust and maintainable. On the other hand, if you're not well versed in the theory, you can fall into several traps. In SQL and Relational Theory, author C.J. Date demonstrates how you can apply relational theory directly to your use of SQL. With numerous examples and clear explanations of the reasoning behind them, you'll learn how to deal with common SQL dilemmas, such as: Should database access granted be through views instead of base tables? Nulls in your database are causing you to get wrong answers. Why? What can you do about it? Could you write an SQL query to find employees who have never been in the same department for more than six months at a time? SQL supports "quantified comparisons," but they're better avoided. Why? How do you avoid them? Constraints are crucially important, but most SQL products don't support them properly. What can you do to resolve this situation? Database theory and practice have evolved since Edgar Codd originally defined the relational model back in 1969. Independent of any SQL products, SQL and Relational Theory draws on decades of research to present the most up-to-date treatment of the material available anywhere. Anyone with a modest to advanced background in SQL will benefit from the many insights in this book.

Sql And Relational Theory

Author : C.J. Date
ISBN : 9781491941133
Genre : Computers
File Size : 72. 38 MB
Format : PDF, ePub, Mobi
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SQL is full of difficulties and traps for the unwary. You can avoid them if you understand relational theory, but only if you know how to put that theory into practice. In this book, Chris Date explains relational theory in depth, and demonstrates through numerous examples and exercises how you can apply it to your use of SQL. This third edition has been revised, extended, and improved throughout. Topics whose treatment has been expanded include data types and domains, table comparisons, image relations, aggregate operators and summarization, view updating, and subqueries. A special feature of this edition is a new appendix on NoSQL and relational theory. Could you write an SQL query to find employees who have worked at least once in every programming department in the company? And be sure it’s correct? Why is proper column naming so important? Nulls in the database cause wrong answers. Why? What you can do about it? How can image relations help you formulate complex SQL queries? SQL supports "quantified comparisons," but they’re better avoided. Why? And how? Database theory and practice have evolved considerably since Codd first defined the relational model, back in 1969. This book draws on decades of experience to present the most up to date treatment of the material available anywhere. Anyone with a modest to advanced background in SQL can benefit from the insights it contains. The book is product independent.

Sql And Relational Theory

Author : C. Date
ISBN : 9781449316402
Genre : Computers
File Size : 57. 1 MB
Format : PDF, ePub, Docs
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SQL is full of difficulties and traps for the unwary. You can avoid them if you understand relational theory, but only if you know how to put the theory into practice. In this insightful book, author C.J. Date explains relational theory in depth, and demonstrates through numerous examples and exercises how you can apply it directly to your use of SQL. This second edition includes new material on recursive queries, “missing information” without nulls, new update operators, and topics such as aggregate operators, grouping and ungrouping, and view updating. If you have a modest-to-advanced background in SQL, you’ll learn how to deal with a host of common SQL dilemmas. Why is proper column naming so important? Nulls in your database are causing you to get wrong answers. Why? What can you do about it? Is it possible to write an SQL query to find employees who have never been in the same department for more than six months at a time? SQL supports “quantified comparisons,” but they’re better avoided. Why? How do you avoid them? Constraints are crucially important, but most SQL products don’t support them properly. What can you do to resolve this situation? Database theory and practice have evolved since the relational model was developed more than 40 years ago. SQL and Relational Theory draws on decades of research to present the most up-to-date treatment of SQL available. C.J. Date has a stature that is unique within the database industry. A prolific writer well known for the bestselling textbook An Introduction to Database Systems (Addison-Wesley), he has an exceptionally clear style when writing about complex principles and theory.

Grundlagen Von Datenbanksystemen

Author : Ramez Elmasri
ISBN : 386894012X
Genre :
File Size : 76. 33 MB
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High Performance Mysql

Author : Baron Schwartz
ISBN : 9783897218352
Genre : Computers
File Size : 83. 88 MB
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Einführungen in MySQL gibt es viele. Wer aber größere MySQL-Server betreut, die verlässlich laufen müssen, egal was Programmierer oder Benutzer auf sie loslassen, der braucht weiter reichende Informationen. In High Performance MySQL beschreiben sechs anerkannte Experten mit langjähriger Erfahrung auf großen Systemen alle Stellschrauben, an denen MySQL-Admins drehen können, um Sicherheit, Performance, Datenintegrität und Robustheit zu erhöhen. Von Profis für Profis Hier geht es nicht um kleine Webauftritte mit Datenbankanbindung! Lernen Sie stattdessen fortgeschrittene Techniken kennen, mit denen Sie MySQLs Potenzial voll ausreizen können -- um große, skalierbare Systeme zu entwerfen, zu optimieren und zu sichern. Behandelt werden Benchmarking, Indizes, Storage-Engines, Replikationen, Lastverteilung und Hochverfügbarkeit, Backups, Sicherheit... und zu jedem Aspekt die richtigen Werkzeuge, mit denen sich Ihre Ziele am besten realisieren lassen. Praxiserprobt muss es sein Der eine ist MySQL-Guru bei Yahoo!, der andere Angestellter Nr. 25 bei MySQL AB und dort nacheinander für das MySQL-Manual, die Trainingskurse und die Entwicklung des Supports zuständig, wieder ein anderer war bei MySQL AB im High-Performance-Team – die Autoren dieses Buchs wissen, wovon sie sprechen. Graue Theorie finden Sie woanders, hier geht es um bewährte Techniken aus der Praxis. Die erste Auflage von „High Performance MySQL“ wurde hoch gelobt und hat schon unzähligen Lesern wertvolle Dienste geleistet. Nun war es an der Zeit, dieses anerkannte Handbuch einmal komplett zu aktualisieren, um nützliches Referenzmaterial zu erweitern, neue Features der Versionen MySQL 5.0 und 5.1 zu ergänzen und zahlreiche Themen wie die Optimierung der Storage-Engine InnoDB zu vertiefen.

Relational Theory For Computer Professionals

Author : C.J. Date
ISBN : 9781449369460
Genre : Computers
File Size : 62. 66 MB
Format : PDF, Kindle
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All of today’s mainstream database products support the SQL language, and relational theory is what SQL is supposed to be based on. But are those products truly relational? Sadly, the answer is no. This book shows you what a real relational product would be like, and how and why it would be so much better than what’s currently available. With this unique book, you will: Learn how to see database systems as programming systems Get a careful, precise, and detailed definition of the relational model Explore a detailed analysis of SQL from a relational point of view There are literally hundreds of books on relational theory or the SQL language or both. But this one is different. First, nobody is more qualified than Chris Date to write such a book. He and Ted Codd, inventor of the relational model, were colleagues for many years, and Chris’s involvement with the technology goes back to the time of Codd’s first papers in 1969 and 1970. Second, most books try to use SQL as a vehicle for teaching relational theory, but this book deliberately takes the opposite approach. Its primary aim is to teach relational theory as such. Then it uses that theory as a vehicle for teaching SQL, showing in particular how that theory can help with the practical problem of using SQL correctly and productively. Any computer professional who wants to understand what relational systems are all about can benefit from this book. No prior knowledge of databases is assumed.

View Updating And Relational Theory

Author : Chris Date
ISBN : 9781449357849
Genre : Computers
File Size : 71. 88 MB
Format : PDF
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Views are virtual tables. That means they should be updatable, just as "real" or base tables are. In fact, view updatability isn’t just desirable, it’s crucial, for practical reasons as well as theoretical ones. But view updating has always been a controversial topic. Ever since the relational model first appeared, there has been widespread skepticism as to whether (in general) view updating is even possible. In stark contrast to this conventional wisdom, this book shows how views, just like base tables, can always be updated (so long as the updates don’t violate any integrity constraints). More generally, it shows how updating always ought to work, regardless of whether the target is a base table or a view. The proposed scheme is 100% consistent with the relational model, but rather different from the way updating works in SQL products today. This book can: Help database products improve in the future Help with a "roll your own" implementation, absent such product improvements Make you aware of the crucial role of predicates and constraints Show you how relational products are really supposed to behave Anyone with a professional interest in the relational model, relational technology, or database systems in general can benefit from this book.

Sql Von Kopf Bis Fuss

Author : Lynn Beighley
ISBN : 9783955619442
Genre : Computers
File Size : 28. 21 MB
Format : PDF, Docs
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Ihre Daten erdrücken Sie? Ihre Tabellen verheddern sich regelmäßig? Wir haben ein Mittel, wie Sie Ihre Datenbanken in den Griff bekommen: SQL von Kopf bis Fuß nimmt Sie mit auf eine Reise durch die SQL-Welt, es geleitet Sie von einfachen INSERT-Anweisungen und SELECT-Abfragen zu knallharten Datenbank-Manipulationen mit Indizes, Joins und Transaktionen. Erwarten Sie dennoch Spaß, gehen Sie davon aus, etwas zu lernen, und machen Sie sich darauf gefasst, dass Sie Ihre Daten wie ein Profi abfragen, normalisieren und verknüpfen werden, noch bevor Sie dieses Buch ausgelesen haben. SQL von Kopf bis Fuß ist in einem visuell abwechslungsreichen Format gestaltet, das sich an den neuesten Forschungsergebnissen aus Kognitionswissenschaft und Lerntheorie orientiert und Ihnen das Lernen so einfach wie möglich machen soll. Das Buch bietet Ihnen ein unterhaltsames Lernerlebnis und spielt Ihnen SQL direkt ins Hirn - und zwar so, dass es sitzt.

Database Design And Relational Theory

Author : Chris Date
ISBN : 9781449328016
Genre : Computers
File Size : 35. 59 MB
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Because databases often stay in production for decades, careful design is critical to making the database serve the needs of your users over years, and to avoid subtle errors or performance problems. In this book, C.J. Date, a leading exponent of relational databases, lays out the principles of good database design.

Sql

Author : Jonathan Gennick
ISBN : 3897212684
Genre :
File Size : 84. 72 MB
Format : PDF, Docs
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