SMS_G_System_ExtHistory is an abstract class from which inventory objects are derived. It contains multiple subclasses named SMS_GEH_System_<resource>, such as SMS_GEH_System_CDROM.
An inventory object can be updated, creating a group of delta versions of the same object differing (at least) by incremental changes in RevisionID. SMS_G_System_ExtHistory contains all the deltas, both current and obsolete. The obsolete records are kept in the system for ninety days by default. The default may be changed using DB Maintenance Tasks.
Table B.61 Extended History Inventory (SMS_G_System_ExtHistory)
| Property | Data type | Example | Notes |
|---|---|---|---|
| GroupID | uint32 | Key. Within one ResourceID (one SMS client), GroupID distinguishes one instance of a class from another. Objects with the same ResourceID and GroupID are “deltas” of one another, describing the same hardware inventory instance at different points in time. | |
| ResourceID | uint32 | 3 | Key. Indicates an identifier for the resource that is unique to this site. System Resource Type inventory items with the same ResourceID were all discovered on the same SMS client. A ResourceID is an integer generated for the sake of SQL. It is not unique outside the site and should be used only for short-term querying purposes. |
| RevisionID | uint32 | Objects with the same ResourceID and GroupID are deltas, differentiated from one another by RevisionID number. The highest number is the most recent update. | |
| TimeStamp | datetime | See “Date and Time Formats” at the beginning of this appendix. | Indicates the creation time (revision time) of this delta. |