The conversion of a 2-Kbyte database to a 4-Kbyte or 8-Kbyte format with the BPGSIZE utility routine has no impact on connected database applications and other databases so long as the database contains only database key values with a REC-REF <= 254 and an RSQ <= 224-1.
In most cases, however, a database will be converted so that the extended value range for database key values (REC REF > 254 and/or RSQ > 224-1) can be used in it. The use of extended database key values usually affects the associated application programs as well as other databases in some circumstances and therefore mandates appropriate adaptation measures.
In order to enable the use of extended database key values in the database, an application program may need to be adapted in the following cases:
The Schema DDL of the converted database contains at least one of the following clauses:
TYPE IS DATABASE-KEY-LONG
LOCATION MODE IS DIRECT-LONG
SET SELECTION THRU LOCATION MODE OF OWNER if the primary key is defined with
LOCATION MODE IS DIRECT-LONG
The application program uses DML statements that access the database via database key items.
The application program uses at least one of the following COBOL definitions:
definition of a COBOL item of type USAGE IS DATABASE-KEY
redefinition with REDEFINES for a USAGE IS DATABASE-KEY item
reference via a LINKAGE to a data structure containing items of type USAGE IS DATABASE-KEY-LONG
(e.g. LINKAGE to a subschema).
The application program uses database key values in areas that are not directly detectable (see section "Adapting additional locations in the application program").
Following the adaptation, the application program must be recompiled and linked again.