The standard way to do this is using element-sets. When you want to
show a list of summary records, request element-set "b" (brief), and
when you want to display a detailed record, request element-set "f"
(full).

(By the way, Z39 is a working group within ANSI/NISO. There are other
Z39 standards, including Z39.2, MARC, and Z39.88, OpenURL. So it's a
very bad abbreviation to use for Z39.50.)

2009/10/14 Eran gi <[log in to unmask]>:
> Hello,
>
> In our application's built-in search engine, the search process includes 3
> steps:
> 1. The user executes a query
> 2. A "preview" of the results is presented, containing the items' titles,
> authors etc.
> 3. When an item is selected, the complete record is presented to the user.
> This way, the system does the relatively expensive task of gathering the
> complete item record only upon demand.
>
> The z39.50 protocol consist of only two steps: searching and getting a list
> of complete records. Due to the way our database is designed, converting our
> native format to marcxml, for instance, requires an export operation, which
> is quite heavy. Having to go through with that before the user can even be
> sure the results are indeed what she was looking for could be quite a
> burden.
>
> The only solution I could think of is supplying a non-standard record schema
> in which only a few selected fields would be returned. Then, if the user
> would like to get the complete records, one of the standard schemas would be
> used. Does this comply with the spirit of z39? will the average client
> understand the idea? is there a better way?
>
> Thanks,
> Eran
>