HP 3000 Manuals HP 3000 Manuals
Chapter 6 The Transaction File
What is the Transaction File?
Each Intrinsic has a short calling sequence, using optional parameters
where possible. You cannot always pass all the information necessary in
these parameters, such information must be passed in a file - the
Transaction File. In this way, the Intrinsic calling sequence can be
kept short.
When sending a message using the Intrinsics, the use of a Transaction
File containing a series of transaction records, each describing a simple
logical part of the overall message, simplifies the level of processing
necessary to build and interpret messages.
Input messages and data contained in the Transaction File are passed from
the calling program to the Driver process. The results of an operation
are passed back to the calling program by the Driver process in the same
Transaction File, or in a new Transaction File.
Transaction Files are used primarily to describe a message as stated
above. However, they can also be used to:
* Define requests over and above what is passed in the Intrinsic
parameters, for example in HPDUtility and HPDDeleteMsg.
* Return results from list or selection requests, for example in
HPDDiary or HPDNameProbe.
* Hold an embedded Distribution List from a message.
* Describe diary items.
* Define Session Profile options.
This chapter describes the transactions used in all of these
circumstances apart from defining Session Profile options which is
described in Chapter 9.
A summary of the benefits of the Transaction File:
* The Intrinsic calling sequence can be kept short
* Its simple format reduces the amount of processing needed to parse
the information
* Enhancements to the product can be made through new or extended
transaction types without affecting established applications