Fundamentals of Database Systems (7th Edition)
Format: PDF / Kindle (mobi) / ePub
For database systems courses in Computer Science
This book introduces the fundamental concepts necessary for designing, using, and implementing database systems and database applications. Our presentation stresses the fundamentals of database modeling and design, the languages and models provided by the database management systems, and database system implementation techniques.
The book is meant to be used as a textbook for a one- or two-semester course in database systems at the junior, senior, or graduate level, and as a reference book. The goal is to provide an in-depth and up-to-date presentation of the most important aspects of database systems and applications, and related technologies. It is assumed that readers are familiar with elementary programming and data-structuring concepts and that they have had some exposure to the basics of computer organization.
Bn)(R) or qS(R) or q(B1, B2, ..., Bn)(R) 1 Page 180 of 893 where the symbol q (rho) is used to denote the RENAME operator, S is the new relation name, and B1, B2, . . ., Bn are the new attribute names. The first expression renames both the relation and its attributes; the second renames the relation only; and the third renames the attributes only. If the attributes of R are (A1, A2, . . ., An) in that order, then each Ai is renamed as Bi. B 7.4.4 Set Theoretic Operations The next group of
department 5 who work more than 10 hours per week on the ‘ProductX’ project. List the names of all employees who have a dependent with the same first name as themselves. Find the names of all employees who are directly supervised by ‘Franklin Wong’. For each project, list the project name and the total hours per week (by all employees) spent on that project. Retrieve the names of all employees who work on every project. Retrieve the names of all employees who do not work on any project. For each
Ed Omiecinski, Girish Pathak, Raghu Ramakrishnan, Ed Robertson, Eugene Sheng, David Stotts, Marianne Winslett, and Stan Zdonick. Last but not least, we gratefully acknowledge the support, encouragement, and patience of our families. R.E. S.B.N. © Copyright 2000 by Ramez Elmasri and Shamkant B. Navathe 1 Page 21 of 893 About the Authors (Fundamentals of Database Systems, Third Edition) Ramez A. Elmasri is a professor in the department of Computer Science and Engineering at the University of
type of degree three ternary. In this section, we elaborate on the differences between binary and higher-degree relationships, when to choose higher-degree or binary relationships, and constraints on higher-degree relationships. Choosing Between Binary and Ternary (or Higher-Degree) Relationships The ER diagram notation for a ternary relationship type is shown in Figure 04.13(a), which displays the schema for the SUPPLY relationship type that was displayed at the instance level in Figure 03.10.
striping 1 Page 109 of 893 may be applied at a finer granularity by breaking up a byte of data into bits and spreading the bits to different disks. Thus, bit-level data striping consists of splitting a byte of data and writing bit j to the disk. With 8-bit bytes, eight physical disks may be considered as one logical disk with an eightfold increase in the data transfer rate. Each disk participates in each I/O request and the total amount of data read per request is eight times as much.