IBM 000-8697 User Manual

System Architecture

Eventually, a row may outgrow its original storage location. If this occurs, a
forward pointer to the new location of the data row is left at the position
defined by the rowid. The forward pointer is itself a rowid that defines the
page and the location on the page where the data row is now stored. (Refer
to

for further information about the role of the forward pointer in

row storage.)

The variable length of a data row has consequences for row storage:

■

A page may contain one or more whole rows.

■

A page may contain portions of one or more rows.

■

A page may contain a combination of whole rows and partial rows.

■

An updated row may increase in size and become too long to return
to its original storage location in a row.

The following paragraphs describe the guidelines OnLine follows during
data storage. Refer to

for further information about the role of the

slot table in data storage. Refer to

 for further information about

the role of the rowid in data storage.