![]() ![]() Commercial relational database systems are systems where data is organized into relations. Whether one is designing databases or reading structured information, it can be useful for understanding to re-formulate data as statements in natural language. Both sentences use natural language to express in words the meaning of tabular data. Woman’s Day has a circulation of 7,535,855.ĭocument sentences and verbalization sentences are essentially the same. National Geographic has a circulation of 10,249,748.īetter Homes & Gardens has a circulation of 8,007,202.įamily Circle has a circulation of 7,611,578. Reader’s Digest has a circulation of 18,094,192. TV Guide has a circulation of 19,547,763. Taking values from a row, we plug values for X and Y into the document sentence to obtain sentence instantiations: Kirsch and Mosenthal use variables (X and Y) to stand for data that comes from a table. ![]() This document sentence expresses an understanding of the tabular data in natural language. magazinesĪ major point the authors make is that such information can be re-conceptualized as a series of simple document sentences formed from a basic document sentence. That data is reproduced in figure 1.2.įigure 1.2 Circulation of leading U.S. In Building Documents by Combining Simple Lists, Kirsch and Mosenthal present an example based on information from The World Almanac and Book of Facts: 1980 (Newspaper Enterprise Association, p. In the Journal of Reading several articles by Kirsch and Mosenthal discuss the organization of information and its conceptualization as document sentences. For example,Įmployee with ID 123 has a first name Joe, a last name Smith, and is of Male genderĮmployee with ID 333 has a first name Jim, a last name Jones, and is of Male genderĪ similar approach to organizing knowledge about data appears in the literature on literacy. In verbalizations like this, the ellipses are placeholders: we can use values from a single row to create complete statements that explain the meaning of a row. A verbalization that fits the information in one row of the Employees table is:Įmployee with ID … has a first name …, a last name …, and is of … gender Information structured in tables is very concise at a glance, we can obtain useful information.Īccording to the database design methodology in Information Modeling and Relational Databases, a database designer must be able to express structured information as verbalizations. Data kept for each employee comprises their employee identification number, their first and last names, and their gender. Let us assume the Employees table in figure 1.1 has one row for each employee who works for some hypothetical company. As tables of data appear in so many places (newspaper articles, textbooks, web pages, etc.) it is very likely you have seen and used this representation for data previously. Each row has a value for employee number, first name, last name, and gender. The name of the table is Employees, each column of the table has its own title, and each row has the same structure. You should notice this looks just like a two-dimensional table of rows and columns. We begin with a very small example: a database with one relation, the list of employees shown in figure 1.1. Codd in 1969 Codd’s 1970 paper is considered one of the great papers in Computer Science. Relational Databases were introduced by E. Because Microsoft Access is a workstation/personal system it is a convenient system for beginners. There are many different commercial relational database systems and what you learn here will assist you in using those others. In this book, we focus on Relational databases and one specific relational database system: Microsoft Access. A database may be on paper or held in computer files such as spreadsheets or more formally in a software system known as a computerized database management system (for example DB2, db4o, IMS, MS Access, MS SQL Server, MySQL, Oracle, Sybase, Total, Versant). ![]() A database is an organized collection of data. ![]()
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