The DATAEXCHANGE option can be set as a data set default, an audit trail specification, or at the structure level. The DATAEXCHANGE option is not allowed for restart data sets, internal structures, or remaps. The DATAEXCHANGE option can also be set for a Data Set using Independent physical options.
When the DATAEXCHANGE option is set for a Data Set, a special audit image is added when either of the following occurs:
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A record of an embedded structure is modified or created
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An ASSIGN statement is performed
The audit image will contain the data record image of the related structure. This is an informational image and is not used for RECOVERY purposes. If a Data Set has DATAEXCHANGE set to true, each of that structures embedded Data Sets will also have DATAEXCHANGE set to TRUE.
DATAEXCHANGE can only be specified for a disjoint Data Set, not an embedded Data Set, variable format disjoint datasets however are permitted. Adding or removing the DATAEXCHANGE option to or from an existing database requires a DASDL update, and will increase the update level of the database. This change will also require a new CONTROL file and a recompilation of DMSUPPORT.
