HP System Dictionary/XL General Reference Manual Vol 1 (32256-90004)

7- 97
Data Item
A data item is an element entity. The sub-item count, type designator and sub-item length of a data item
is stored in the element attributes count, element-type and byte-length, respectively.
Example
To define the data item NAME, create the element NAME with the following attributes:
count = 3
element-type = X
byte-length = 30
Data Set
A data set is an image-dataset entity. The data set type is stored in the data set attribute image-dataset-
type. A manual master data set has the image-dataset-type MANUAL. An automatic master data set has
the image-dataset-type AUTOMATIC. A detail data set has the image-dataset-type DETAIL.
For each data set there should be a record entity occurrence that defines the record layout for that data set
entry. Each element (data item) that is in that data set should be related to the record with a specified
byte-offset for the relative position of that element within that record. The record should be related to the
data set entity occurrence that it describes. This relationship is established with the image-dataset
contains record relationship type.
Typically, only one record is related to a data set to define a data set entry layout. However, you have the
flexibility of defining more than one record layout for an image-dataset entity. Each image-dataset can
have one primary record layout which is indicated with the image-dataset contains record relationship
type attribute primary-record.
Example
To define the data set CUSTOMER, create the data set CUSTOMER with image-dataset-type equal to
MANUAL.
Create the record CUSTOMER-REC to define the record layout of data set CUSTOMER.
Create the elements ACCOUNT, NAME, and CITY.
Relate each of these elements to record CUSTOMER-REC using the record contains element relationship
type. The byte-offset for ACCOUNT is 1, for NAME is 5, for CITY is 95.
Relate CUSTOMER-REC to CUSTOMER using the image-dataset contains record relationship type.
Search Item
The search item of a master data set is defined by the image-dataset key element relationship type. That
is, the element (search item) is related to the MANUAL data set for which it is a key. Note that the
primary record layout for this data set should contain this element. Also note that there is no need to
establish a key for an AUTOMATIC data set since the primary record layout should contain only the
search item.