The UPDATE-SQL willl be slow if it updates multiple records because it locks/unlocks each record. The REPLACE command places lock on the table for the duration of execution.

>Which is better between #1 and #2 below and is there a big performace difference between the two.
>
>1.) Performing 20 of these commands:
> REPLACE myfield1 WITH var1 IN mytable
> REPLACE myfield2 WITH var2 IN mytable
> REPLACE myfield3 WITH var3 IN mytable
> etc...
>
>VS
>
>2.) Performing 1 of these commands:
>UPDATE mytable SET field1 = var1, field2 = var2, etc...
> WHERE myprimaryfield = somekey