Unique Values or Records?

[nh]

Please can somebody please explain to me the difference
between Unique Values and Unique Records. I have found
several definitions in help files and on the web, but none
of them make it very clear.

I often use Unique Values, but think that in some cases it
would be better to use Unique Records.

Thank you

Nick

 

[Nikos Yannacopoulos]

Nick,

Unique values imposed on a table field does not allow a single value to be
repeated in the same field in more than one record. To do that on a table
field, select it in design view and set the Indexed property to Yes (No
duplicates).

Unique records means that values in a particular field can be repeated in
several records, but not all field values in a given record can be the same
as in another one, at least one has to be different. This is not a property
you can set in a similar manner to a previous one; in order to enforce
unique records on a table, you must select all fields in design view and set
them as Primary Key (Edit > Primary Key). This will force the table to
accept unique combinations of field values only.

HTH,
Nikos

 

[John Spencer (MVP)]

Unique Values means that the combination of all the fields in the select clause
of the query will be unique. So it combines all the records based on the values
you are displaying in the query.

Unique Records means that the combination of all the fields in the records (not
just those displayed) determines how the rows are combined.

So given two records with 3 fields
John P Spencer
John C Spencer

Unique values when you are returning just the first name and last name would
give you one record with Unique values
John Spencer
and two records with Unique Records
John Spencer (with a non-visible P)
John Spencer (with a non-visible C)