HP Integrity NonStop J-Series - Manual (Page 169)

USING AN ENABLE APPLICATION
READ EXACT
READ APPROXIMATE Operation for a Nested Box
For a nested box, you can perform a READ APPROXIMATE operation
only if a key field appears in the box. (If a key field does not
appear and you request a READ APPROXIMATE operation, the
application will perform a READ EXACT operation.) If a key field
appears, do the following to request a READ APPROXIMATE
operation:
1. Read or insert a record in the containing box.
2. Enter a value in the key field of the nested box.
3. Press F6.
READ EXACT (F7)
To retrieve the first record (or records) with a key field value
that exactly matches the one you have entered, request a READ
EXACT operation. If you enter a value for a primary key field,
the application returns the single existing record. If you enter
a value for an alternate key field that has duplicate values, the
application retrieves the first record (or records) that has that
alternate key value.
If the key field is a group key field, you must enter a value for
all the fields in the group. Consider, for example, the
following group key field:
+ DEPT
REGNUM __
BRANCHNUM __
To request a READ EXACT for the DEPT field, you must first enter
a value in both REGNUM and BRANCHNUM. If you enter a 1 in REGNUM
and do not enter a value in BRANCHNUM, the application will not
find a record unless REGNUM = 1 and BRANCHNUM = 0.
8-16