Dictionary/3000 Reference Manual (32244-90001)

Chapter 3 45
Using the DICTDBM Commands
Using Commands to Define HP Inform/3000 Groups
• If only one of the elements can link all the files, then give it a high priority link value (1)
and let the link values of the others default (0). * If more than one element is needed to
link the files, give a link value of 1 to the one that should be tried first, 2 to the one that
should be tried next, and so on. Use -1 if you never want the element to be used as a
link and 0 (the default) if the element could be used if needed.
NOTE An element can link two files only if it exists in both files and if certain
additional requirements, depending on the file being linked to, are met. See
Appendix D, How HP Inform/3000 Links Files to Generate Reports, for more
information on linking.
Elements assigned a positive link value form a prioritized list to be used when it is
necessary to link files. The lower the positive integer assigned to an element, the higher
the likelihood that it will be used as a link. In general, you should assign a link value of 1
to the element that will link the most files containing elements for the group, 2 to the
element that will link the next most, and so on. This will ensure that the reports an HP
Inform/3000 user requests from a particular group will be generated efficiently.
Table 3-1 summarizes the priorities of the possible link values:
Note that if an element has different meanings in different files (for example, the data
element "date" may have different meanings in different files), you will not want it to be
used as a link even if it links all the files containing elements for the group. Give such a
data element ("date" ) a link value of -1. (Note that in this case, simply answering the
FILE prompt, without specifying a link value of -1, will cause the correct values for "date"
to be printed in the report but will not help to link the files correctly.)
By both responding to the FILE prompt for an element and assigning a positive link value
to the element, you are designating a potential "driving file" . The driving file is the file
that is accessed first. Since at least one line of the report will be generated for each record
retrieved from the driving file, the contents of a report could be quite different if the
driving file is different. By designating a potential driving file, you are specifying that file
should be accessed first whenever:
• any element from the group which exists in that file is requested for the report, and
Table 3-1. Link Value Priorities
Link Value Priority
1 Highest priority
2 Next highest priority after link value of 1
3 Next highest priority after link values 1 and 2.
..
..
n Next highest priority after link values 1, 2, ...n-1
-1 Never used as a link