Prestwood: Data Element Naming Standard

From the February 2010 Issue of Prestwood eMag

DBA & Data: Data Element Naming Standard

By Jeffrey Tyzzer

7/1/1996, Last updated 4/30/2007

Take Away: This paper articulates the standard for naming data elements (entity attributes).

DBA KB Article:

Tags: database , standard , standards , data element , naming

by Jeffrey K. Tyzzer

Introduction

This paper articulates the standard for naming data elements (entity attributes). This standard is a component of Information Technology's overall data standards program, which includes fully-attributed data models, entity and attribute naming standards, and entity and attribute definition standards. The purpose of these standards is to promote data reuse and ensure consistency of data representation.

Principles

Data element names are the primary means by which users of the data identify and interact with data elements. Names are formulated according to rules that are independent of a specific natural-language syntax, and must be brief, clear, and free of physical context. Data element names imply only concepts which are represented in the element's definition.

Composition

Data element names are composed of three constituents: prime words, class words, and modifiers (also called qualifiers).

Prime Words:

Represent the business concept about which data are being collected.
Describe the subject area of the data.
Are a noun or noun phrase which describes the subject and main focus of the name.
Place data elements within the logical context of the information model.

Examples: Loan, Customer, Employee, Property

Class Words:

Identify a distinct category or classification of data.
Delineate the type of data being described by the data name.
Describe the major classification of data associated with a data element.

Class words can be grouped into the following distinct sub-classes:

Chronology

Examples : Date, Day, Month, Year

Measurement

Examples: Amount, Balance, Rate, Quantity, Hours

Identification

Examples: Number, Code, Indicator

"Number" is used to identify an entity.

"Code" is used to represent encoded values.

"Indicator" is used to represent the existence of a condition, i.e., a truth-valued (boolean) flag.

Text

Examples: Name, Description, Comment

Modifiers:

Further qualify or distinguish the prime and class words.
Provide clarity and uniqueness to the data name.
Modify both class and prime words.
Restrict the meaning of the class and prime words.

Examples: Last, First, Next, Previous, Beginning

Business and Access Names

When modeling a problem domain, two versions of a data element name are required: the business, or descriptive name, and the access name.

The business name is the unabbreviated natural language name of the data element expressed as a noun phrase -- it provides the meaning (NOT the definition -- although, at times, the distinction may be blurred) of the data. The business name should be clear to all users of the data, regardless of subject matter expertise. Note also that the business name may not contain any action verbs, i.e., the business name "Date borrower applies" is unacceptable; it should be replaced with "Borrower application date".

Example: Last name of Borrower

The access name is an abbreviation of the business name, which can be constrained by implementation concerns (e.g., character length).

Example: BORRWR_LAST_NAME

Constructing the Access Name

Clarity is enhanced when data element access names are constructed the following way:

PRIME WORD: MODIFIER(S) : CLASS WORD

There exist occasions when other combinations of this format may be used for semantic purposes.

Strongly Encouraged Guidelines (i.e., Rules):

If adherence to these rules inhibits communication of the purpose of the attribute, the rule(s) may be bent.
Only one abbreviation per word.
Always abbreviate words five or more characters long.
Words less than or equal to four characters in length should not be abbreviated.
The first letter of the abbreviation should equal the first letter of the word.
An abbreviation should not be a word. For example, an abbreviation for the business name "Account Number" called "ACCNT_NO" would be unacceptable, because "NO" is a word. Use "ACCNT_NUMBER" instead.
When conforming to implementation-specific character length limitations, eliminate vowels first, then eliminate the least semantically-significant letters or words.

Foreign Keys

There is an ongoing debate concerning whether or not to include the entity name in the attribute name. The guidelines outlined above do not address this issue directly, but often the prime word will convey the same meaning.

One instance where it may be useful to extend the "prime word: modifier(s) : class word" structure is in the naming of foreign keys. One approach to naming foreign keys is to include the name of the "home entity" in the foreign key (the home entity is the entity where the field originates).

by Jeffrey K. Tyzzer

Introduction

Principles

Data element names are the primary means by which users...