My earlier blog entry on the topic “What is an item?” created a good level of conversation. And since we are talking about engineers, the more interesting question turned out to be, “What is NOT an item?”
We shall use the English term “item” in this context. The Swedes usually talk about articles (artikel). Of course, there are no scientific definitions on the topic (yet) so we shall ponder about this on laymen’s level. Just for giggles, I checked an online dictionary to see how they define “item”:
1. It is quite extraordinary how many rare items some collectors have. An item of clothing, French items on the list were shipped to Brazil.
2. The next item on the agenda, the first item on the programme
3. A newspaper item
The word “itemize” is also there:
“itemize [‘aɪtəmaɪz] (also itemise) to create a detailed list, I asked him to itemize the price. Steinburg itemised 32 design faults in the reactor.
We can easily see that there is no ready-made technical glossary that specifically understands companies’ material items but that’s a story for a later time…
A drawing is not an item
In any case, this definition is very close to the point. So, an item in the product data management framework refers specifically, with the indefinite article, to a certain concrete thing (not necessarily only an object) that can be a material, an assembly of parts, an end product, a service product, a software product, an electronic component etc. At this stage, I have always stated that a drawing is not an item. It is a document that usually depicts how an item is manufactured. So, can we conclude that a document is not an item? Well, I wouldn’t be quite that strict…
A variant is an instrument
A customer once asked whether a variant is an item? I said not in my opinion, which of course led to a long debate that might or might not have ended in a tie. The same person told me that their whole product portfolio is described using one variant item from which customer-specific deliveries are made by using order-specific attributes. Future generations will only get hold of a list of sales attributes instead of a top-level item. I still maintain that an item is always an unambiguous description of its target. In that sense, the online dictionary’s “to create a detailed list” is a good definition for “itemize”. In an item, all the definitions or attributes describing its features are always itemized in an unambiguous manner. A variant can be seen as an instrument with which it is possible to easily manage a group of different items. (I hereby refer to my old blog entry, “Death to code keys”)
Is an individual serial number an item? A serial number in its unique concept is not an item. However, it does represent an item.
Is a spare part an item? What an interesting question. According to one definition, an item becomes a spare part as soon as the item information is linked with its application and of course information on whether the part in question has been defined as a spare part. It is the application that dictates the spare part feature, not the item itself. In practice, a spare part is an item but an item is not a spare part.
A document is an attribute
Let’s return to the document. Why would a document not be an item? Or what is it for example in conjunction with the item of “pressure vessel”? A pressure vessel that has a certain capacity, material information, ability to withstand pressure, etc., is simply an item. However: for this pressure vessel item to be approved in a PDM system, the related documentation by authorities must be approved. In other words, an item cannot exist without certain documents. In this case, a document can be seen as an item’s attribute.
If you are creating structural maintenance documentation in which a document is compiled according to the end product’s product structure, and in which each product module is linked with its own document section, these document elements can very well be called items. And because the maintenance log is an organic part of customer delivery, it is its own item that, in the best case, even has its own price.
I have now conveniently filled a page. Readers, grab your keyboards and continue to ponder from here on. Like I said, no scientifically approved definition exists. Dissertations have been written on less significant topics so some academically aware person could grab the ball…
– PDM Preacher