An Introduction to ISO 15926 November 2011 - iRINGToday

temp dTemp Normal Operating Temperature degF
press dPress Normal Operating Pressure psig
ifc dateIFC Issued for Construction Date yyyymmdd
Again, without having to change the construction application in any way she builds an import
function that expects to receive attributes with names from the common dictionary and maps
them to the attribute names in the construction application. There are several advantages to
using a common dictionary that are important to note.
• The developer of the engineering application does not have to know anything at all about
the construction application. Indeed, he does not even have to know it exists.
• The developer of the construction application does not have to know anything at all about
the engineering application—beyond, of course, knowing that it is the source of certain
input data.
• Both of the developers are now free to modify their respective applications in any manner,
including massive changes to their data structure—as long as the output and input are
mapped to the same common dictionary.
• Both developers know the precise meaning of the input/output from each other’s application
because they know the precise meaning of the dictionary term they are mapped to.
We call this “semantic precision.”
Of course, there is a cost to developing a common dictionary. Someone has to herd the cats
together to decide on the meaning of each term and what to call them. This is not trivial.
Many people, each with different interests and agendas, have to look at the applications in
question—possibly having to make fine distinctions between very similar attributes, as well as
build in some allowance for growth.
In short, there is a great deal of initial work in making a common dictionary but in a large
organization it is recouped whenever a new application joins the confederation. For instance,
when a procurement officer needs information from the engineering application to use in a
procurement application instead of examining the content of the engineering application’s
database all a software developer has to do is consult the dictionary and determine the values
he wants to use.
Procurement App Dictionary ID Description Units
tag szTag Tag Number of a plant object
dia dDia
Nominal Diameter per ASME/ANSI
B36.10
len dLen Pressure Class per ASME/ANSI B16.10
ifc dateIFC Issued for Construction Date yyyymmdd
The fact that the engineering application is exposing other data attributes is not of interest.
The procurement application (Figure 1.11) will simply choose the four data items it needs and
use them. Creating the common dictionary made the first mapping exercise take a bit longer,
but the benefits are clear.
• The second (and third, and fourth) mapping exercise is almost free. When the developer
of the procurement application wanted to import line list information from the engineering
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