Notes

• Global variables can be used in queries, procedures, and forms. Preface a variable with one or more ampersands (&) when you use it in a QMF object.
• A global variable name can contain a numeric character, but the first character of a global variable name cannot be numeric.
• The first character of a global variable name must be an alphabetic character (A through Z) or one of these special characters:

   ¢  !  $   ~   {  }  ?
   @  #  %  \

• A global variable name cannot contain blanks or any of the following characters:

   .  ,  ;  :  <  >  (  )  |  +  -  *  /
    =  &   ¬  '  "

• Variable names are limited to 17 single-byte characters (or the equivalent in double-byte characters). Character constants do not need to be enclosed in single quotes.
• In REXX, values for global variables are limited to 55 characters.
• On the SET GLOBAL command, variable names are not preceded with an ampersand like they are on the RUN and CONVERT commands.
• Global variable names with question marks are not recognized by the QMF form.
• Global variables set to form variable names or aggregation variable names are not recognized by the QMF form.
• Global variable names cannot begin with DSQ, because QMF reserves these letters for QMF predefined global variables.
• Trailing blanks are not recognized in global variable names.
• If a variable is a character string that is a name (such as the name of a column, a table, or an operator):
  • Double all embedded quotation marks.
  • Enclose the complete string in a set of single quotation marks. (These quotation marks are not considered part of the value.)

  For example, if the SELECT statement is:

    SELECT DEPT, &COL FROM &TABLE

  The SET GLOBAL command is:

    SET GLOBAL (COL='NAME', TABLE='Q.STAFF'

• If the variable is a character string that is to be used as a value contained within a column (unique to the WHERE clause in an SQL statement) you can use either of two methods to specify a string.

  Method 1 (quotes)

  1. Start with the original string.
  2. Double all quotation marks (if any).
  3. Enclose the string in two sets of single quotation marks.
  4. Double all the embedded quotes (all but the outermost ones).

  Method 2 (parentheses)

  1. Start with the original string.
  2. Enclose the string in one set of parentheses.

  For example, if the SELECT statement is:

    SELECT DEPT FROM &TABLE WHERE NAME=&ABC

  The Method 1 SET GLOBAL command is (substituting JAMES for variable ABC):

    SET GLOBAL (ABC='''JAMES''', TABLE='Q.STAFF'

  The Method 2 example for the same SELECT statement is (substituting O'BRIEN for variable ABC):

  SET GLOBAL (ABC=(O'BRIEN), TABLE='Q.STAFF'

• If the variable contains a blank, comma, single quote, double quote, or an equal sign, the entire value must be enclosed in a set of parentheses. However, if the value includes an unmatched set of left or right parentheses or begins or ends with a left or right parenthesis respectively, you must use quotes instead.

  For example, if the SELECT statement is:

    SELECT &COLS FROM Q.STAFF

  The SET GLOBAL command is:

    SET GLOBAL (COLS=(NAME, JOB, SALARY)

• At least one variable must be specified.
• If a quotation mark is required within a variable value, use two single quotation marks.
• Do not use a query comment as variable value. A query comment is preceded by two dashes (--), which the database interprets as minus signs.
• When you are setting many variables, it's easier to keep track of them if you use a procedure.
• If the variable is a numeric string, you do not need to use quotation marks.
• If the variable name is not found in the QMF product global variable pool, a new variable is created.
• If variable name is found, the new value replaces the old value.