Magazine article Online

Making the Most of Practice Databases

Magazine article Online

Making the Most of Practice Databases

Article excerpt

It may be called a Practice, Training or ONTAP file, but this type of small database is a microcosm of its larger parent database. Using such a subset file is an inexpensive way to learn how to use some of the more expensive databases.

BRS has eight Practice databases on BRS/Search, and most are also available on BRS/Colleague, BRS/After Dark, and BRS/Instructor. They cost $10/hour, plus telecommunication fees, and citations are free of charge.

Data-Star has 16 Training databases that are free except for telecommunication charges. Focus users have access to a special demonstration file, but not to the Training databases.

DIALOG has 42 ONTAP databases that cost $15/hour, plus telecommunication fees, with free citations. Library schools have access to ONTAP files, but they are not available to Knowledge Index users.

EPIC has 15 Practice databases with connect hour charges that range from free to $10/hour. There are no citation charges but there is a network service fee. The Practice databases are not available on FirstSearch.

DATABASE CHARACTERISTICS

Practice databases are small subsets of major databases, and represent a cross-section of various types of databases available from the databanks. They may contain as few as several hundred records to as many as 187,000 records. Most, however, contain from about 15,000 to 65,000 records. These records are representative of the content of the parent database and may be from a specific time period (e.g., September 1 through December 5, 1977 for DIALOG'S ONTAP CA SEARCH) or contain selected records from several years (e.g., 16 years between 1966 and 1990 on BRS Practice MEDLINE), or another kind of mix. Usually practice databases have older information and are not intended to be used to answer real questions. Some, such as ERIC and CA SEARCH, contain citations from the late 1970s. The other omnibus files, MEDLINE, EMBASE, BIOSIS Previews, and SciSearch, contain records from the late 1980s and early 1990s.

Practice databases are static files and are seldom updated unless there are major enhancements or a reload of the parent database. Practice database dates and their size can be found in search service catalogs, online database descriptions such as BRS File, and brief database pages such as Bluesheets and Aid Pages.

On DIALOG it is easy to check for available years in the ONTAP files by entering EXPAND PY=, which displays the range of years in the file. On the newly reloaded Practice MEDLINE on BRS, a new SpeedSearch technique, ..ROOT YR= displays the range of years. However, on other BRS and Data-Star practice files, enter the two or four-digit year with the .YR. qualifier and guess at a range of years.

One limitation of practice databases is that all the subjects available in the parent file may not be available in the practice subset. So when planning a practice search strategy, pick subjects for which there were likely to be plenty of articles published. Don't look for rare case reports or obscure authors.

Another limitation is that all special features or commands may not be operational in practice databases. Specifically, commands that involve multidatabase searching may not function in the practice files. For example, on BRS the ..LINK command that automatically retrieves the full text record from Comprehensive Core Medical Library does not work between Practice MEDLINE or Practice EMBASE and the Practice Complete Text Journals. On Data-Star, StarSearch is not operational for the Training databases. The SAVE commands work on BRS and DIALOG, but not on Data-Star. On DIALOG, the MAP command that creates a saved search of data extracted from a specific field such as CAS Registry Numbers is operational as is the OneSearch multidatabase search feature.

PRACTICE FILES FOR HEALTH SCIENCE SEARCHERS

Health science searchers are fortunate to have so many practice databases of potential interest. …

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