Using QMF

Substitution variables

Another way to use a model is to set substitution variables for the values that you want to change.

A substitution variable can represent anything that you can write into a query, such as a column name, a search condition, or a specific value. You supply the value for a substitution variable in the "&variable" option on the RUN command or the RUN Command Prompt panel. You can specify the substitution variable on a SET GLOBAL command (instead of RUN) before you run the query.

For example, if you want a list of the employee IDs, names, and jobs of everyone in each of several different departments, you could construct the query like this:

Q.STAFF | ID | NAME   | DEPT        | JOB  |
--------+----+--------+-------------+------|
        | P. | P. AO. | &DEPARTMENT | P.   |

If you run this query without a value on your RUN command, a Prompt panel displays. On the Prompt panel, you fill in a value to substitute for the variable in the query.

When the value to substitute for the variable is one of the following:

A single valid numeric value

Specify the desired value.

Text without embedded quotes, parentheses, blanks, equal signs, or commas

Specify exactly as desired.

Text with embedded quotes

Enclose the entire value in quotes. (Quotation marks are not removed when QMF makes the substitution.)

Text with embedded parentheses, blanks, equal signs, or commas

Enclose the entire value in parentheses. (The outer parentheses are removed when QMF makes the substitution.)

You could write the following query, for example:

Q.STAFF | NAME      | DEPT   | JOB   | COMM       |
--------+-----------+--------+-------+------------|
        | P. AO.    | &DEPT  | P.    | P.         |

When you run this query, you can specify the variable value:

RUN QUERY (&DEPT = 38

QMF then reads the query like this:

Q.STAFF | NAME      | DEPT   | JOB   | COMM       |
--------+-----------+--------+-------+------------|
        | P. AO.    | 38     | P.    | P.         |

Substitution variables make it possible for other people to use your query. Other users can substitute any value in place of the variable and produce a report specific to their needs. For example, if your RUN command does not supply values for the variable as is shown in the following command:

COMMAND===> RUN REPT4QRY

QMF displays a prompt panel:

               RUN Command Prompt -- Values of Variables
 
Your RUN command runs a query or procedure with variables that
need values.  Fill in a value after the arrow for each variable
named below:
 
&DEPT              ===>
                   ===>
                   ===>
                   ===>
                   ===>
                   ===>
                   ===>
                   ===>
                   ===>
                   ===>
                   ===>
 
Press Enter to execute the command from this panel.
 
13=Help     15=End
Please give a value for each variable name.
ISPF Command ===>

Enter the desired department number after the arrow on the panel. For example:

&DEPT    ===> 84

A substitution variable can be a whole name or be included in part of a name.

Substitution variable names:

• Can be no longer than 18 characters, and the first character must be an ampersand (&).
• Can contain only these characters:
  • Letters of the alphabet
  • National characters: @ # $
  • Special characters: &splitvbar. % ? ~ ` { } \ | &cent !
  • Numbers
  • Underscores (_)
• Can be separated from another variable or command word by any of the characters that are not mentioned above, such as commas, blanks, or parentheses.