POSC Specifications
Version 3.0 |
Epicentre Modeling
Methodology |
Naming Conventions
POSC has established conventions for naming data modeling
objects, including entities, attributes, rules, and schemas.
Names shall be referenced by application programs using the
application program interface.
The model names for schemas, entities, attributes, defined
types, and rules conform to the following rules and
guidelines.
Content Rules
- E&P Data Model names are restricted to use the 26
lowercase English alphabet characters, number characters 0-9,
and underscore.
- Special characters, including brackets, quotation marks,
question marks, slashes, commas, stops and hyphens are not
allowed in a name.
- Component words that form a name should be separated by
an underscore.
- Names shall not start with a number or an underscore
character.
- Names for schemas, defined types, and rules are variable
length strings of a maximum width of 40 characters.
- Names for entities and attributes are variable length
strings of a maximum width of 30 characters.
- Complete names shall not be the same as any EXPRESS
language reserved phrases, or as any SQL3 reserved
words.
Content Guidelines
- A name should be in a singular form.
- Do not use prepositions, conjunctions, articles, "and,"
"or," or other superfluous words in a name.
- Avoid redundant qualifier words (redundant because they
appear elsewhere in the context).
- The position of a qualifier word in a name should depend
on its significance to the name, i.e., place the most
significant qualifier word in the front.
Standard Prefixes
The model uses some standard name prefixes to aid
understanding. These are:
- Pty - for names of all property subtypes.
- Ndt - for names of all named defined types.
- Ref - for names of most reference entities.
Name Scope
Names of entities, attributes and rules are unique within
some scope. The scope rules are those of EXPRESS:
- Entity names shall be unique within a schema.
- Attribute names shall be unique within the scope of the
parent entity, which includes all of its subtypes.
- Local rule names shall be unique within the scope of the
parent entity.
- Global rule names shall be unique within the scope of the
schema.
Reserved Words
Epicentre names cannot coincide with any of the reserved
words of EXPRESS or of SQL3.
The list of reserved words and phrases is given below. They
are taken from Tables 1, 2, 3, 4, and 5 of ISO 10303-11, and
ANSI X3H2-93-004.
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