A primary key constraint is implimented as a unique index at the physical
level. They are identical. But the added benefit of declaring PK constraints
is that it enables you to use that table in replication. Additionally, it
provides meta data for modeling apps and such, and shows how your tables are
related in the relational model.


Hi,

For column A, I need to make it unique and also index it. Does it the same
as put an unique index on this column?

I think they will work the same, but wonder if there is anything I oversee
by choosing one over the other. Any performance consideration here?

Thanks,
Elaine









---------------------------------------------------------------------
To unsubscribe, e-mail: mssqldba-[Email Address Removed] additional commands, e-mail: mssqldba-[Email Address Removed]MS Sql Server LazyDBA home page