RE: Create Lists

["Fox, Linda J." <FoxLJ@xxxxxxxxxx>]

At 10:52 PM 1/19/00 David T. Jones wrote:

> Also, make sure to keep at least two lists big enough to deal with the
> entirety of the largest set of records that you have (probably item
> records). You never know when you are going to need to search and find
> almost all of the records in your database....

While that's a nice idea, it's not always practical.  We currently have over 6.5
million item records in our database....

Also, it is probably not the most practical way to allocate your resources.  By
all means keep a few very large review files for those occasional large lists.
We currently have six files that can contain at least 100,000 records; the
largest is 240,000.  We have found, however, that most of our needs can be met
with files containing 1000 or 5000 records.  Our current file structure is:

      1,000    45
      5,000    64
     10,000    32
     20,000    17
     30,000     5
     40,000    10
     60,000    11
    100,000     3
    140,000     1
    160,000     1
    240,000     1
We frequently find that we must use files larger than necessary because all the
small ones are in use.

If you should ever have to find more records than can be contained in the
largest file you have, you can create multiple review files.  Either find a way
of retrieving records in logical groups (for example, by location), or wait
until the first file fills up, then limit your search so that it begins with the
record immediately after the last one in the first file.  (We used a combination
of these methods about a year ago to find 447,442 records.)  Of course this can
create problems if you need to have all the records in a sequence other than the
one used to create the files (say by author), but creative use of additional
review files to pull out records from the original set (file one has authors
A-G, file two has H-M, etc.) should work.

You might also want to set up some ground rules, especially if your review files
will be used by more than a few staff members.  We have two rules which seem to
us to be critical: always use the smallest possible file and always empty a
review file when you are done. Other rules include a naming convention that
includes the identity of the person who created the file, and never empty
someone else's file.  Again, depending on the number of folks involved, you
might want to write these rules down and make sure everyone has a copy.  If you
have a staff website, put it there as well. 

Most of our rules relate to high demand for review file use.  As we gain
experience with creating review files and how they can be useful for everything
from generating statistics to claiming periodicals to doing rapid updates to
creating bibliographies, and as we spread the word to our coworkers, more and
more of us are creating more and more review files.  Because we are a consortium
of libraries from five academic institutions, the number of persons who might
want or need to create a review file is well in excess of 100.  Even with these
simple rules, occasionally the word must go out to empty unnecessary review
files.  We have added review files more than once (we currently have 200), and
will probably do so again.

Hope you find this helpful.

Linda Fox
Library Assistant, Technical Services Division
304 Miller Nichols Library
University of Missouri--Kansas City
5100 Rockhill Rd.
Kansas City, MO  64110

phone: (816) 235-5290
fax: (816) 333-5584
email: foxlj@xxxxxxxxxx