References Between Databases

A Database (DB) often contains elements which have reference or reference array attributes which point into other DBs. For example, one Model DB could contain a Branch connected to a Nozzle in another Model DB. The HREF (or TREF) attribute of the Branch would point into the second DB and the CREF attribute of the Nozzle would point back into the first DB.

Similarly, references can exist from Model DBs into Catalogue DBs (the SPREF attribute of a piping component pointing to an SPCOM, for example), but references cannot exist from a Catalogue DB back into a Model DB.

When a DB is reconfigured without the SAMEREF option, most of the reference numbers of its elements will change. To maintain the integrity of pointers into the DB from other DBs, the contents of any DB which might point to elements in the reconfigured DB are scanned and the reference or reference array attributes are changed to point to the correct element once more.

For example, assume that the reference number of an SPCOM in a Catalogue DB changes from =17/3108 in the original DB to =49/2014 in the reconfigured copy. All piping components whose SPREF attribute was previously set to =17/3108 must have SPREF reset to =49/2014. Such components might exist in several DBs.

Reference resetting is performed by the RCFUPDATE command described in the next section.