by Sanjay Mishra

O'Reilly Media

Chapter 1 Oracle Utilities Pocket Reference Introduction The Oracle database comes with many tools and utilities that are useful to the database administrators, system administra- tors, and application developers. With increasing demands on productivity, these tools and utilities are as valuable to an Oracle database professional as a screwdriver or hammer to a builder. Some utilities are well known and well documented (such as sqlldr, lsnrctl, and so on), whereas some are not so well understood. Some are as old as Oracle itself (e.g., sqlplus, oerr, and so on), whereas some are as new as Oracle Data- base 10g (such as expdp, impdp, etc.). This book provides a quick-reference guide for using these Oracle utilities. If you are an experienced database profes- sional and know the utility you need, you can use this book to quickly find the syntax of the utility. If you are a beginner, you can use

(2004)

eBook €7.00

by Sanjay Mishra and Alan Beaulieu

O'Reilly Media

Chapter 1 CHAPTER 1 Introduction to SQL In this introductory chapter, we explore the origin and utility of the SQL language, demonstrate some of the more useful features of the language, and define a simple database design from which most examples in the book are derived. What Is SQL? SQL is a special-purpose language used to define, access, and manipulate data. SQL is nonprocedural, meaning that it describes the necessary components (i.e., tables) and desired results without dictating exactly how those results should be computed. Every SQL implementation sits atop a database engine, whose job it is to interpret SQL statements and determine how the various data structures in the database should be accessed to accurately and efficiently produce the desired outcome. The SQL language includes two distinct sets of commands: Data Definition Lan- guage (DDL) is the subset of SQL used to define and modify various data structures, while

(2007)

eBook €27.00

The Definitive Guide

by Jonathan Gen... and Sanjay Mishra

O'Reilly Media

Chapter 1 1 In this chapter: • The SQL*Loader Environment • A Short SQL*Loader Example • SQL*Loader’s Capabilities • Issues when Loading Data • Invoking SQL*Loader Introduction to SQL*Loader SQL*Loader is an Oracle-supplied utility that allows you to load data from a flat file into one or more database tables. That’s it. That’s the sole reason for SQL*Loader’s existence. The basis for almost everything you do with SQL*Loader is a file known as the control file. The SQL*Loader control file is a text file into which you place a description of the data to be loaded. You also use the control file to tell SQL*Loader which database tables and columns should receive the data that you are loading. Do not confuse SQL*Loader control files with database control files. In a way, it’s unfortunate that the same term is used in both cases. Database control files are binary files containing information

(2008)

eBook €27.00