================================================ SEARCHDATABASE.COM'S DBA Tips and Tricks May 16, 2001 ================================================ Welcome to the searchDatabase.com DBA Tips and Tricks newsletter! Today's tip, "The relational database model" can also be viewed online at: http://www.searchDatabase.com/tip/1,289483,sid13_gci552875,00.html ************* Sponsored by Syncsort ************* **Mine Web Data Fast!-FREE Flashlight-FREE Trial** An active web site can easily generate a billion web records a day. How can you mine all that information fast to better understand customer behavior and increase profits? Web data mining pioneers like Microsoft are using SyncSort, a lightning-fast data manipulation product, to sort, select, reformat, clean, standardize and aggregate web data. For a FREE product trial, and a FREE flashlight to remind you that SyncSort can shine a light on buried nuggets of information fast, click here: http://www.syncsort.com/tgb510 ************************************************ ------------------------------------------------ LEARNING ZONE FEATURED BOOK OF THE WEEK ------------------------------------------------ "SQL: The Complete Reference" By James Groff The book provides an in-depth discussion of SQL fundamentals and features, as well as a conceptual framework and insight into relational database technology and its trends. The Bonus CD-ROM contains over $900 worth of free software from the leading SQL vendors, including Windows 95/NT versions of Microsoft SQL Server 7, Oracle8, Informix, Sybase, and IBM DB2. http://www.digitalguru.com/dgstore/product.asp?isbn=0072118458&ac_id=58 ************************************************ "The relational database model" By Ryan Stephens & Ronald Plew With a general understanding of the different types of databases and database environments, the database designer can draw more intelligent conclusions about how to proceed with any database system design effort. As discussed in this excerpt from Ryan Stephens & Ronald Plew's new book "Teach Yourself Database Design" (Sams, 2000), there are numerous database models (types) available: * Flat-file database model * Hierarchical database model * Network database model * Relational database model * Object-oriented (OO) database model * Object-relational (OR) database model The modern database of choice is the relational database (RDB). So why is the relational model so attractive? * It is the most stable. * RDB standards are well established by organizations such as the International Standards Organization (ISO) and the American National Standards Institute (ANSI). * There are many RDB vendors to choose from, including Oracle, Microsoft, Informix, IBM, and Sybase. * It is easy to convert between different relational database implementations. * It is easy to define and maintain data with SQL. * It is easy to manipulate data with SQL. * The ad hoc query process is simple. * Data is well-protected through referential integrity and other constraints. The following subsections discuss the relational dastabase in a bit more detail that will assist in your overall understanding for designing a relational database. First, the characteristics of a relational database are discussed as outlined by the creator of the relational model. Then, the various objects that are most commonly found in a relational database are outlined. Relational Database Characteristics ----------------------------------- The relational model was designed by the IBM research scientist and mathematician, Dr. E.F. Codd. Two of Dr. Codd's main focal points when designing the relational model were to further reduce data redundancy and to improve data integrity within database systems. The relational model originated from a paper authored by Dr. Codd entitled, "A Relational Model of Data for Large Shared Data Banks," written in 1970. This paper included the following concepts that apply to database management systems for relational databases: * A relational database management system (DBMS) must be able to manage databases entirely through its relational capabilities. * All information in a relational database (including table and column names) is represented explicitly as a value in tabular format. * Every value in a relational database is guaranteed to be accessible by using a combination of the table name, primary key value, and column name. This means that you need not know the physical location of the data, and that you can directly access any row of data in a database table independently. * The DBMS should provide support for the treatment of null values (unknown or inapplicable data), which are distinct from default values, and independent of any domain. * The description of the database and its contents is represented at the logical level in tabular format and can therefore be queried using the database language. This refers to metadata that is stored in the data in regards to the database itself. Metadata is data about other data. Click here for a description of the remaining characteristics as well as relational database objects: http://www.searchDatabase.com/tip/1,289483,sid13_gci552875,00.html "Teach Yourself Database Design" (Sams, 2000) is available for purchase here: http://www.digitalguru.com/dgstore/product.asp?isbn=0672317583&ac_id=58 ------------------------------------------------ FOR MORE INFORMATION ------------------------------------------------ The Best Database Design Web Links: http://searchdatabase.techtarget.com/bestWebLinks/0,289521,sid13_tax283234,00.html Have a database design tip to offer your fellow DBAs and developers? The best tips submitted will receive a cool prize! 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