Dictionary/3000 Reference Manual (32244-90001)

Appendix D 331

How HP INFORM Links Files to Generate Reports

Indirect Links

If two ﬁles containing elements needed for a report are linked through other ﬁles which

contain no elements needed for the report, the link is called an “indirect link”. There are

only two indirect links which HP Inform/3000 allows and both apply only to data sets

within the same database. These links are the following:

1. If a master set needs to be linked to another master, a link can be made by going

through a detail which has a search item in common with each of the masters. For

example, assume the following is a partial representation of a data base:

Suppose the report requests the data element “zoning-des” from the master set

ZONING-MASTER and the data element “city-name” from the master set

CITY-MASTER. An indirect link can be made by going through the detail set

COMMERCIAL. The master set ZONING-MASTER has the search item “zoning-code”

which forms an IMAGE path to the detail set COMMERCIAL, and the master set

CITY-MASTER has the search item “city-abbr” which also forms an IMAGE path to

COMMERCIAL.

2. If a detail set needs to be linked to a master set, a link can be made by going through a

second detail which has a search item in common with the ﬁrst detail (forming IMAGE

paths to a common master) and a second search item forming an IMAGE path to the

desired master. For example, assume the following is a partial representation of a

database:

*zoning-code

zoning-des

*city-abbr

city-name

*zoning-code

*city-abbr

ZONING-MASTER CITY-MASTER

COMMERCIAL

*search items