What\'s the equivalent of Oracle\'s RowID in SQL Server?
Several of the answers above will work around the lack of a direct reference to a specific row, but will not work if changes occur to the other rows in a table. That is my criteria for which answers fall technically short.
A common use of Oracle's ROWID is to provide a (somewhat) stable method of selecting rows and later returning to the row to process it (e.g., to UPDATE it). The method of finding a row (complex joins, full-text searching, or browsing row-by-row and applying procedural tests against the data) may not be easily or safely re-used to qualify the UPDATE statement.
The SQL Server RID seems to provide the same functionality, but does not provide the same performance. That is the only issue I see, and unfortunately the purpose of retaining a ROWID is to avoid repeating an expensive operation to find the row in, say, a very large table. Nonetheless, performance for many cases is acceptable. If Microsoft adjusts the optimizer in a future release, the performance issue could be addressed.
It is also possible to simply use FOR UPDATE and keep the CURSOR open in a procedural program. However, this could prove expensive in large or complex batch processing.
Caveat: Even Oracle's ROWID would not be stable if the DBA, between the SELECT and the UPDATE, for example, were to rebuild the database, because it is the physical row identifier. So the ROWID device should only be used within a well-scoped task.