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

2.6 The SQL Buffer

SQL*Plus keeps a copy of the most recently entered SQL statement or
PL/SQL block in an internal memory area known as
the

SQL
buffer ,


often
referred to as the buffer . Command-line SQL*Plus
needs a place to store your statement or block until you are finished
entering it. SQL*Plus provides you with the ability to edit the
statement in the buffer. This can be a real convenience if you make a
mistake halfway through typing a long, multiline query.

SQL*Plus buffers SQL statements and PL/SQL blocks, but not SQL*Plus commands. For example, the DESCRIBE command would not be buffered but a SELECT statement would be. To help make the distinction, think in terms of where the command is executed. If you enter something to be executed by the database server, then it is buffered. If it's a command local to SQL*Plus, then it is not buffered.

SQL*Plus provides two ways to edit the statement currently in the
buffer. The first method is to use the set of line-editing commands
built into SQL*Plus. The second method is to use the EDIT command to
invoke an operating system-specific text editor, such as Notepad in
the Windows environment, or vi under Unix.

If you are editing a statement in the buffer, be sure you don't forget yourself and execute any other SQL statement. Even a simple SQL statement like COMMIT will overwrite the buffer. Commands to SQL*Plus, such as the editing commands, do not affect the buffer.

There are some other useful things you can do with the buffer. If you
have several similar SQL statements to execute, using the buffer can
save you the effort of completely typing out each one. You may be
able to enter the first statement, execute it, make a minor change,
execute the new statement, and so on, until you are done. SQL*Plus
also allows you to save and load the buffer to and from a text file,
allowing you to store frequently executed statements for later


use.