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close this book Food Composition Data: A User's Perspective (1987)
close this folder Managing food composition data
close this folder Concerns of users of nutrient data bases
View the document (introductory text)
View the document Introduction
View the document Accessibility
View the document Installation and updating efforts
View the document Data availability
View the document Computational concerns
View the document Data-base and software products
View the document References

Installation and updating efforts

Installation and updating efforts

The effort required to install and maintain a nutrient data base depends on the specific characteristics of the installation. Because of the effort required when a data record format is changed, a standard format that can remain stable for an extended period of time is desirable. Each time the data record format from a depository is modified, users must either recreate their data bases and reformat data of local interest prior to merging with new data or reformat the new data to be compatible with their existing data-base design.

Many data-base developers utilize nutrient profiles for ingredients to estimate the nutrients in mixed dishes. Information about the quantity of each ingre client is stored in recipe data bases along with cross-referencing codes used to retrieve the nutrient profiles from a nutrient data base when the nutrients per portion are calculated. These recipe data bases facilitate the recalculation of nutrient profiles for mixed dishes by computer. The recalculation process can be involved at different times: periodically, such as monthly; whenever the contents of the nutrient data base are changed; whenever a change is made in the recipe formulation; or when a dietary record is processed with a mixed dish coded as a consumed item. With the maturation of computerized systems for food production and patient care, the use of recipe data bases is more prevalent, particularly in health-care organizations. For these users, the overhead associated with a data record format change is multiplied, since a recipe data base may also require recreation and associated software must be modified to process the new data structures.

Since conversion is expensive and time-consuming, some users may need the opportunity to acquire new data without being required to change to a new data format. Users with minimal resources or limited technical support must be able to maintain compatibility with existing software.

Data should be available in machine-readable form. Manual data entry is time consuming and error-prone; the probability of locating mistakes is low. Verified data from a reputable source in machine-readable form helps to assure the integrity of nutrient data bases.

Since so many data bases are updated with nutrient profiles for brand-name products and fast foods, a clearing-house or depository for brand-name product information is needed. These data should also be distributed in machine-readable form. The numbering scheme for these products should be co-ordinated with the coding scheme adopted by depositories providing nutrient profiles for generic foods. Also, the measuring units for the amount of food and food constituents should be consistent with those available for generic foods.

A universal or standardized code would be useful to some users to facilitate data-base updating and inter-data-base communications. In a survey of data-base developers conducted in March 1984 by the Data Base Committee of the Ninth National Nutrient Data Bank Conference, 28 of a total of 52 respondents preferred a standardized code or vocabulary.

Recoding within an existing system when the keys to data records are changed is a major task. Cross-reference or linking files are needed to facilitate recoding in other associated data bases such as recipe files. These linking files, which contain the new code number paired with the former code number for each food item, should be available in machine-readable form.

Another practice which would benefit end-users when a new coding system is adopted is application of the new coding system to all food items in an existing data base at one time. Even though new data may not be available at a given time for all entries in the data base, this approach would permit users to accomplish conversion to the new coding scheme and data structure as a single task rather than having to repeat the recoding task each time new data are released. However, if new data are not provided for some of the food items or some items are deleted, users should be informed so that they can replace the obsolete codes with new ones in associated data bases, such as recipe data bases.

Availability of data from a primary depository in user-specified formats would permit customized data bases to be downloaded so that minimal technical expertise would be required of the end-user. On-line retrieval is desirable when the amount of data can be accommodated by a user's equipment and data-transfer costs are economical.

Maintaining compatibility with existing software and other computerized systems reduces the overheads associated with installing new data bases or updating existing ones. Many nutrient data-base users in health-care organizations must compete with other users in their facility for support from the data-processing department. Efficient use of those resources is necessary when data-base conversion is required. Thus, multiple optional arrangements for data transfer would allow users to avoid some installation and updating costs.