4.4 The Roots of SQL

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Why are we going backwards in time looking at data models and relational databases that are no longer in use? In order to tune SQL code effectively we need to understand the most basic forms of SQL and why newer data modeling techniques are better. In short, database access coding (SQL coding in the case of a relational database) has evolved with data modeling techniques. Object database data access coding has been called ODQL. ODQL stands for Object Definitional Query Language. ODQL was developed for object database access.

SQL in actuality stems from an idea of a reporting language devised in theory by the inventor of the relational database. It is very important to remember that the roots of SQL lie in retrieval of sets of data. In other words, SQL is intended as a language to retrieve many rows from one or many tables at once, as a result set. Retrieval of sets or groups of rows is consistent with the original relational data model. SQL was not originally intended to retrieve individual rows from a relational database as exact row matches. SQL can now be used to do exactly that, and fairly efficiently.

The next chapter is the first chapter in Part II of this book, SQL code tuning. We will begin the process of explaining SQL code tuning by introducing the very basics of SQL. In subsequent chapters of Part II we will progress onto the most fundamental aspects of SQL code tuning, then later to specifics of using and tuning Oracle SQL.



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Oracle High Performance Tuning for 9i and 10g
Oracle High Performance Tuning for 9i and 10g
ISBN: 1555583059
EAN: 2147483647
Year: 2003
Pages: 164

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