IntroductionCHAPTER 1 traces the history of the development of SOL from E.F.Codd's articles in the early 1970s,setting forth the principles of arelational database,through the Chamberlin articles of the late1970s,to the latest publications of the American National StandardsInstitute (ANSI)in their efforts to develop a standard SOL language.CHAPTER 2 sets forth the notation and defines the terms usedthroughout the book.CHAPTER 3 contains an overview of all of the components of con-ventional SOL language.the SOL comnds,key words.datatypesand value expressions supported by SOL.The three in types ofstatements-Data Definition,Data Manipulation,and Data Control-are listed and the syntax for each is shown,as well as the syntax forthe various expressions.connectives,predicates,and functions thatke up the SOL language.CHAPTER 4 contains explanations and examples of the use of SOLtable expressions and predicates in preparation for using them to setup a database in the next chapter.CHAPTER 5 illustrates the use of the Data Definition statementsCREATE,ALTER,and DROP,and gives examples of these statements asthey are used to define and modify tables in an illustrative databasesystem.CHAPTER 6 illustrates the use of the Data Manipulation com-nds INSERT,UPDATE,DELETE,and SELECT.Because creating views(unlike creating tables)involves data nlpulation,it is included inthis chapter.CHAPTER 7 explains the use of the Data Control statements,bythe persons who must administer the database,and discusses thesecurity and integrity constraints that y be invoked using SOL.CHAPTER 8 shows the use of aggregate functions,logical operatorsand subqueries as they are employed in SOL,and includes examplesof the use of NOT with each of these.CHAPTER 9 is devoted exclusively to the topic of joins becausejoins can add a great deal to the efficlent use of a relational database.Equijoins and non-equijoins are explained,as well as the Cartesianproduct.natural joins,and outer joins.CHAPTER 10 is a detailed discussion of views.With a well-destgneddatabase,the end user will be using views most of the time ratherthan base tables.At the same time,not all operations possible withtables are possible with views.Therefore,SOL operations on views areexplained and the view-update problem is discussed.In CHAPTER 10the use of indices is discussed.This leads to a discussion of the opti-l fortion of queries to speed up the retrieval process.CHAPTER 11 discusses the elements of relational algebra andrelates them to SOL.SOL has been said to "resemble"the tuple rela-Introductionrelational algebra and the relational calculus.CHAPTER 12 develops the elements of the first-order logic neededfor the tuple relational calculus as discussed by E.F.Codd in an earlyarticle.Interpretations as developed in the propositional calculus andextension in the predicate calculus to a database scheme is exhibit-ed.This database scheme is then shown to be an interpretation deter-mining a form of the predicate calculus known as the tuple relationalcalculus.The extension of the idea of an interpretation is shown todetermine what is retrleved by means of a query formulated in thetuple relational calculus.Finally,the examples and exercises showhow the tuple relational calculus queries are converted to SOLquerles.Thus,chapter 12 demonstrates the theme by which SOLdeveloped from the need for a query language through first-orderlogic to a user-friendly relational database intece.CHAPTER 13 presents "embedded SOL,"a form of SOL that can beembedded in computer programs and converted to host languagecode with a precompiler.Cursors (implementor-defined work areasfor holding relational tables obtained from queries)are discussed,aswell as the embedded SOL comnds for nipulating cursors.Thegoal in chapter 13 is to present embedded SOL as it now exists underthe current ANSI Standard and most current implementations with-out limiting the presentation to any one implementation.Suggestionsare de for modifying the embedding process to ke the program-mers task less onerous and more likely to produce bug-free pro-grams.These suggestions are demonstrated by examples of SOLembedded in short C language modules.which programmers canmodify to fit their own implementation and requirements.CHAPTER 14 describes the use of SOL in some of the principalcommercial relational databases and SOL servers now on the rket.CHAPTER 15 describes the requirements that must be met by acommerclal database in order to claim confornce with the ANSIstandard.A Glossary defines all words relevant to SOL,as well as all rela-tional database terms that the reader might need to know in connec-tion with this topic.A Bibliography provides the interested reader with additionalsources of infortion on all of the topics covered.i