SQL (Structured Query Language) is the heart of a relational database management system. It's the language used to query the database, to create new tables in the database, to update and delete database fields, and to set privileges in the database. This text is aimed at everyone who needs to access an Oracle database using SQL - developers, DBAs, designers, and managers. SQL is based on research dating back to the late 1960s, but its first commercial release was in the RDBMS announced by the fledgling Oracle Corporation in 1979. Since that time, every other database vendor has adopted SQL, and ANSI and the ISO have made it a standard. Although vendors diverge in their extensions to SQL, the core language is standard across vendor boundaries. Despite SQL's long history and relative simplicity, few developers and database administrators are truly masters of SQL. The constant stream of vendor enhancements, the hard-won experience in tuning SQL for best performance, and the requirements of particular operational environments mean that there is always more to learn about SQL. "Oracle SQL: The Essential Reference" aims to deliver the information needed to keep ahead of the learning curve on standard SQL and Oracle's extensions to it. There are chapters on: basic SQL elements (naming requirements, column types, pseudo-types, data conversion rules, operators); Data Definition Language (DDL) and Data Manipulation Language (DML); common language elements (constraints, storage clause, predicates); SQL functions; PL/SQL (including procedures, functions, and packages); SQL*Plus, and Oracle SQL optimization and tuning. The book covers Oracle 8i, release 8.1.6.