Types of Substitution Variables

Use iSQL*Plus substitution variables to:

1. Temporarily store values

• Single ampersand (&)
• Double ampersand (&&)
• DEFINE command

2. Pass variable values between SQL statements
3. Dynamically alter headers and footers

You can use single ampersand (&) substitution variables to temporarily store values.  You can predefine variables in iSQL*Plus by using the DEFINE command. DEFINE creates and assigns a value to a variable.

Interactive effects are not restricted to direct user interaction with the WHERE clause. The same principles can be used to achieve other goals. For example:

• Dynamically altering headers and footers
• Obtaining input values from a file rather than from a person
• Passing values from one SQL statement to another.

ISQL*Plus does not support validation checks (except for data type) on user input.  Note: A substitution variable can be used anywhere in SQL PLUS and iSQL*Plus commands, except as the first word entered at the command prompt.