Oracle SQL*Plus: The Definitive Guide, 2nd Edition

Chapter 4. A Lightning SQL Tutorial

SQL is the language that you use to manipulate relational data. Other languages for data manipulation do exist, but SQL is the most common, and it's the reason for the "SQL" in "SQL*Plus." Because everything you do in SQL*Plus will involve SQL, it's worth digressing for a chapter to focus on learning the rudiments of the language.

Data Manipulation Statements

As manifested in Oracle, the SQL language encompasses several categories of statements: statements that work with data, other statements that define and modify the structures (such as tables and indexes) that hold data, and still other statements that control the operation of the database itself.

This chapter focuses on statements used to manipulate data:

INSERT

Places new records, or rows, into a database table.

SELECT

Retrieves previously inserted rows from a database table.

UPDATE

Modifies data in a table.

DELETE

Deletes data from a table.

MERGE

Brings a table up to date by modifying or inserting rows, as appropriate

The reason I focus on data manipulation in this chapter is that if you're just starting out with SQL, data manipulation is likely to be your first problem. You'll likely be working with tables and other database objects that have been created. Furthermore, data manipulation statements are the ones you'll need to leverage the SQL*Plus reporting capabilities I describe in the next few chapters. Other topics, such as creating database structures (e.g., tables and indexes) and controlling the ...