Pathmaker Programming Guide

Creating a DB Requester Application
Pathmaker Application Development Overview
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4. A message is sent containing the entered data to the standard service for that
operation.
5. The standard service performs the operation on the database and returns a
message.
6. The message is displayed on the screen indicating whether or not the operation
was successful, returning data to the end user, if appropriate.
File Types
You can create a DB requester application for the following file types:
Entry-sequenced
Key-sequenced
Relative
If you want to access entry-sequenced or relative files using a DB requester
application, the file must have an alternate key. The Pathmaker product does not
support courtesy keys.
You cannot create a DB requester application that accesses unstructured files.
NonStop SQL Keys
A DB requester application that accesses NonStop SQL tables uses key columns to
identify specific rows in a table.
Three categories of keys exist for NonStop SQL tables:
Primary keys
Indexes
SYSKEYs
A Primary key is a column (or columns) in a table whose value is used to uniquely
identify each row in that table.
An index is a column or group of columns that can be used to identify one or more
rows in a table. An index can contain duplicate values.
The columns of any multicolumn primary key or index do not have to be contiguous.
A SYSKEY is a system-generated number that uniquely identifies each row in a table.
A NonStop SQL SYSKEY can only be displayed or used in a DB requester application
that accesses a protection view that includes that SYSKEY.
A table can have either of the following:
A primary key and any number of indexes
A SYSKEY key and any number of indexes.