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Oracle Tips by Burleson |
Oracle Tables and DML
In this chapter, we are going to discuss Oracle database
tables; how to create and manage them. Tables are the bases for a
relational database. Other database objects will be introduced in
Chapter 5.
Once we have an understanding of Oracle tables and
how data is stored in them, we are ready to move to manipulating the
data. So far, we have just pulled information from the database.
How did that data get there, and how can we change the data already in
the database? This is the function of the INSERT, UPDATE and DELETE
statements. Together, they are referred to as data manipulation
language
(DML).
DML vs. DDL
DML changes data in an object. If you insert a row into a
table, that is DML. You have manipulated the data. When you create,
change or remove a database object, it is referred to as data
definition language (DDL). As we will discuss at the end of this chapter, all DDL
statements issue an implicit commit, so they are a permanent change.
All DML statements change data and must be committed before the change
becomes permanent.
The above text is
an excerpt from:
Easy Oracle SQL
Get Started Fast Writing SQL Reports with SQL*Plus
ISBN 0-9727513-7-8
by John Garmany
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