What's the difference between a primary key and an RRN?
A:
A Primary key identifies a row in a table.
An RRN (I presume you mean Relative Record number) also identifies a row by position in a subset (ie. a query result).
I've found it useful if you need to extrapolate a sequential order for a set of records not related to the primary key.
BigChrisDiD
2010-03-23 05:20:02
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Anil
2010-03-23 13:08:44