Oracle SQLPlus [Electronic resources] : The Definitive Guide, 2nd Edition نسخه متنی

9.2 Limitations of SQL*Plus

When using SQL*Plus to extract data, keep in mind some limitations.
Because SQL*Plus was designed as a reporting tool and not a data
extraction tool, the output must be text. If you need to write a file
containing packed-decimal or binary data, SQL*Plus is not the tool to
use.

A second SQL*Plus limitation you may encounter (but you probably
won't) when extracting data is the line size. On
many platforms, the upper limit for the SET LINESIZE command is
32,767 characters. Unless you want to deal with spreading data from
one logical record over multiple, physical records,
you'll need to keep your output line size at or
under the maximum line size for your platform.

Finally, SQL*Plus was designed to work with traditional, scalar
datatypes. If you're going to use SQL*Plus as an
unloader, you'll find it works best for the
following types of data:

VARCHAR2 NVARCHAR2 NUMBER DATE ROWID CHAR NCHAR
These types can be converted to character strings, and you can
concatenate those strings together to produce whatever output format
you want, whether comma-delimited, tab-delimited, or fixed-width.
Text is the key to extracting data with SQL*Plus. Think text. If you
have nonalphanumeric data to extract, you should use a different
tool.