Record Serial Numbers

A record serial number (RSN) is a unique number (48-bits long) that is associated with a record in a data set. The RSN is guaranteed to be unique, and it stays with a record for the life of the record. Updates do not affect the RSN; therefore, RSNs are ideal keys for DATABridge tables. However, RSNs are available only when using DMSII XE.

DMSII XE adds the RSN to every record of a data set that has the EXTENDED attribute set. As long as the EXTENDED attribute is set, DATABridge can access the RSN, unlike application programs that can access the RSN only if it has been explicitly declared in the DASDL source. The DATABridge Engine is designed to use RSNs instead of AA values whenever possible. Regardless of whether RSNs are present, AA values are used for data sets that contain embedded data sets or DMSII links.

Since RSNs and AA values are the same length, they are interchangeable, unless the data sets are embedded data sets or contain DMSII links. If the DATABridge Engine is not handling either of these types of data sets and an RSN is present, DBEngine uses the RSN rather than the AA value. In this case, the resulting column of the DATAITEMS client control table is named my_rsn instead of my_aa to differentiate it from an AA value. In both cases, the set_name column of the DATASETS client control table will have a value of aa_set.