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Introducing Databases

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Introducing Databases A database is an organized collection of information. A relational database is a collection of related information that has been organized into structures known as tables
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Introducing DatabasesIntroducing DatabasesA database is an organized collection of information. A relational database is acollection of related information that has been organized into structures known as tables.Each table contains rows that are further organized into columns. You should already befamiliar with information being represented in the form of a table with columns. Forexample, Table 2.1 shows the details of some products sold by the Northwind Company.Table 2.1 lists the product ID, name, quantity per unit, and unit price for the first 10products; this information comes from the Products table of the Northwind database. Table 2.1: SOME ROWS FROM THE PRODUCTS TABLEPRODUCT ID NAME QUANTITY PER UNIT Unit Price1 Chai 10 boxes x 20 bags $182 Chang 24-12oz bottles $193 Aniseed Syrup 12-550ml bottles $104 Chef Antons Cajun Seasoning 48-6oz jars $225 Chef Antons Gumbo Mix 36 boxes $21.356 Grandmas Boysenberry Spread 12-8oz jars $257 Uncle Bobs Organic Dried Pears 12-1lb pkgs. $308 Northwoods Cranberry Sauce 12-12oz jars $409 Mishi Kobe Niku 18-500g pkgs. $9710 Ikura 12-200ml jars $31You can store the information in a database on paper in a filing cabinet or in electronicformat stored in the memory and file system of a computer. The system used to managethe information in the database is the database management system. In the case of anelectronic database, the database management system is the software that manages theinformation in the computers memory and files. One example of such software is SQLServer (this is the relational database management system, or RDBMS, used in this book).Other examples of RDBMS software include Oracle and DB2.Note You must be careful to differentiate between a database and a database management system. A database is an organized collection of information, and a database management system is the software that stores and provides the tools to manipulate the stored information. This distinction is blurred these days, so the term database is often used to refer to the software.Another term you need to be familiar with is a database schema, which is a representationof the structure of data, and includes the definition of the tables and columns that makeup the database.In the next section, youll explore SQL Server.

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