Pathmaker Programming Guide

Controlling Default Screen Layout
Creating Requesters
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Link Info. You can use the Record Instance Detail screen to specify linkage information
(Link Info) for DB requesters.
Link Info consists of a set of fields used to link a child record or table to a parent
record or table. Notice that you use a bottom-up approach when you implement a
parent-child relationship using the Pathmaker product: you use the Record Instance
Detail screen of the child record to indicate the linkage between parent and child.
Here are some restrictions on linking files and tables:
NonStop SQL allows you to create a table with more than one column declared as
the primary key. Enscribe allows you to create a file with a group data item
declared as the primary key. A key that is composed of more than one column or
more than one field is called a composite key.
You cannot use a composite key to link DB requesters that access NonStop SQL
tables. You can, however, use a composite key to link DB requesters that access
Enscribe files.
Enscribe and NonStop SQL create system-assigned keys for relative tables. In
Enscribe, this type of key is called a courtesy key. In NonStop SQL, this type of
key is called a SYSKEY.
You cannot use a courtesy key or a SYSKEY to link DB requesters.
The Link Info fields are:
Parent Field Name Used to specify the join field of the parent reference object. You
must fully qualify the join field of the parent reference object.
Child Field Name Used to specify the join field of the child reference object. You
do not need to fully qualify the join field of the child reference
object because the current record is the child record.
Place At Used to determine where the child reference object is to be
displayed. If you specify L (Link field), the Pathmaker product
displays the child reference object immediately after the join
field of the parent reference object. If you specify E (End), the
Pathmaker product displays the child reference object after the
parent reference object’s last field.
When you link a child reference object to a parent reference object, only the parent
reference object is shown on the application screen. The fields of the child reference
object will appear on the screen within a box composed of dashed lines.
The Place At field determines where on the application screen the box will appear:
either immediately following the link field or at the end of the entire reference object.
If a DB requester has more than one record associated with it, it has more than one box
on the screen.
Repetition. You can specify a value for Repetition on the Record Instance Detail screen.
Repetition applies only to DB requesters and pertains only to reference objects. In this
context, a reference object can only be a record or table.