An access path describes the order in which the rows are

retrieved from a database file. If the rows in the file are

accessed in a physical sequence, that is known as an

arrival sequence access path. If the rows need to be

processed in an ordered manner, then a keyed access path is

needed to sort the data in the specified order. With DB2

for iSeries, keyed access paths are supplied to DB2 by

creating a keyed logical file, keyed physical file, or SQL

index.

An access path and an open data path are used together to

process the rows in a database file.

The open data path (ODP) is the path through which all

input and output operations are performed on a database

file. The ODP is used to connect the requesting program

with the data in the file. As data is retrieved from or

inserted into the file, the ODP will use an access path to

navigate to a row within in the file. If the rows need to

be processed in a sorted owner, then someone will need to

supply a keyed access path by creating a keyed physical

file, keyed logical file or SQL index.

An ODP is created and used each time that a file is opened

or when an SQL statement is executed. There are ways to

have an ODP shared or reused instead of creating the ODP

each time.