The Internal Sequence Number (ISN)


When PriceIt encounters a price that needs updating within a document it needs to know which record key that price is associated with. It derives this vital piece of information from the ISN (Internal Sequence Number) which accompanies every markup. Essentially, the ISN acts as a grouping number that allows all fields to be linked to the record key that they belong to. During the process of marking up, PriceIt automatically handles the allocation of these ISN's, with a new one being assigned to each record key as it is marked. This becomes the 'current' ISN that is used to mark each field until the next record key is marked.


Because of this sequence, you should always mark a document by first highlighting a record key and then marking all the fields that relate to this key before moving on to another key. If you need to go back and make alterations later, then you need to ensure that you are working with the correct ISN beforehand. This is achieved using the 'current key' click box within the edit palette - refer to Chapter 5 for more details.


It is important to note that PriceIt always uses this ISN to locate the relevant information, regardless of the document layout. This means that the correct procedure must be followed to markup a document, whether it is in a regular layout, such as a table, or a more random and unstructured format such as a mailshot or flyer. 


Note also that the ISN has no significance in terms of the external data, but is purely used internally by PriceIt. There is therefore no requirement that the ISN should match any aspect of the external data - PriceIt always uses the Record Key information to locate data from the external file.