Hi.
To protect the table from adding duplicate records, you can assign a unique
index to the table. A primary key qualifies as a unique index -- with the
added benefit that no record will be assigned a NULL value in that unique
index. This primary key can be a single column or multiple columns -- as
long as every record has a different set of values in these particular
columns.
However, you can't assign a primary key or unique index to your table other
than on the AutoID column because there are already duplicates. Either
remove the duplicate records or fix them by hand (alter each duplicate record
so that it is unique from all other records). Only then can you assign a
primary key (or unique index) to the table. The primary key (or unique
index) requires all current and future records to be unique, so any attempt
to add a duplicate record will fail.
HTH.
Gunny
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