Chapter 3
Getting to Know SQL
IN THIS CHAPTER
Seeing where SQL came from
Seeing what SQL does
Looking at the ISO/IECSQL standard
Seeing what SQL doesn’t do
Examining your SQL implementation options
In the early days of relational database management systems (RDBMS), there was no standard language for performing relational operations on data. (If you aren’t sure what an RDBMS is, please take a look at the first chapter in this book.) A number of companies came out with relational database management system products, and each had its own associated language. There were some general similarities among the languages because they all performed essentially the same operations on the same kinds of data, structured in the same way. However, differences in syntax and functionality made it impossible for a person using the language of one RDBMS to operate on data that had been stored by another relational database management system. (That’s RDBMS, if you missed it the first time.) All the ...
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