Dictionary/3000 Reference Manual (32244-90001)

330 AppendixD
How HP INFORM Links Files to Generate Reports
Direct Links
Direct Links
A link between two files, each of which contains the values of one or more elements needed
for a report, is called a “direct link”.
When two files are linked, the value of the link element is retrieved from the first file and
is used to determine the correct record to retrieve from the second file. If the link is from
an IMAGE master set, IMAGE detail set, KSAM file, or MPE file to an MPE file, the link
element must simply exist in both files; if the file you are linking to, however, is an IMAGE
master, IMAGE detail, or KSAM file, there are additional requirements on the link
element. These are:
1. If the file you are linking to is a KSAM file, the link element must be a common element
(must exist in both files) and must be a key item in the KSAM file. Note that when the
link is from a KSAM file to another KSAM file, the link element need only be a key item
in the second file accessed.
2. If the file you are linking to is an IMAGE detail set, the link element must be a common
element and must be a search item in the detail set. These are the only requirements
even when the link is from one database to another. Note that when the link is from a
detail set to another detail set, the link element need only be a search item in the
second file accessed.
3. If the file you are linking to is an IMAGE master set, the link element must be a
common element and must be a search item in the master set. These are the only
requirements even when the link is from one database to another. Note that when the
link is from a master set to another master set, the link element need only be a search
item in the second file accessed. (There are two additional ways that a data set can be
linked to a master set as long as the link is within one database; these are explained
below under Indirect Links.)
The following table summarizes the above requirements for direct links according to what
type of file is being linked to. Note that the file you are linking from can be any type - MPE,
KSAM, IMAGE detail, or IMAGE master.
FILE BEING LINKED TO REQUIREMENT ON LINK ELEMENT
MPE Common element.
KSAM Common element which is a key item in the KSAM file
being linked to.
DETAIL Common element which is a search item in the DETAIL
data set being linked to.
MASTER Common element which is a search item in the MASTER
data set being linked to.
EXAMPLE 1 at the end of this appendix demonstrates direct links from an MPE file to a
KSAM file and from an MPE file to an IMAGE detail set.