Writing Natural Language Rule Statements — a Systematic Approach Part 26: Some Common Syntactic Components of Rule Statements
About this series of articles
While my first series of articles on writing natural language rule statements explored a wide variety of issues in a rather organic and hence random manner, this series takes a more holistic and systematic approach and draws on insights gained while writing my recently-published book on the same topic. Rule statements recommended in these articles are intended to comply with the Object Management Group's Semantics of Business Vocabulary and Business Rules (SBVR) version 1.0.
The story so far
In earlier articles in this series (see the "Language Archives" sidebar) we have looked at standardised rule statements for various types of operative rules (data rules, activity rules, and party rules) and definitional rules. Each specific type of rule statement has a common formulation which we have discussed in both a relatively informal way and by way of rule statement patterns.
In the last few articles we looked at the syntax of data cardinality rule statements, data content rule statements (including spatial data constraint statements and temporal data constraint statements), data update rule statements, activity rule statements and party rule statements in general. In this article we shall look at some of the syntactic components that may be found in rule statements of all types.
These are used in rule statements of all types, including:
- in the predicate of a data cardinality rule statement where the required data item is part of a complex data item (an object in a transaction for which more than one individual data item is specified, such as a passenger, high value item, credit card, or postal address in a Travel Insurance Application), e.g.,
- for each passenger
- for each high value item (if any)
- for the credit card
- in the postal address (if any).
- in the subject of a data content rule statement or data update rule statement, either to define the transaction in which the data item is constrained, e.g.,
- in each Travel Insurance Application
or where the constrained data item is part of a complex data item, to define that complex data item, e.g.,
- for each passenger
- in the subject of any other type of rule statement
- in the predicate of various types of rule statement, in particular temporal data non-overlap constraint statements and activity rule statements
- in the constraint expression in an activity rule statement.
The simplest form of prepositional phrase consists of:
- a preposition, such as for, from, in, of, on, to, or (in the case of a temporal constraint) after, before, during, earlier than, later than
- an optional determiner, such as a, an, any, each, that, the
- a term, such as passenger, credit card.
Prepositional phrases can also be chained, e.g.,
- from any boundary of that land parcel
- in the billing address in each online order
- to the price of each item in that order.
Prepositional phrases can also be combined using and or or, e.g.,
- after pushback and before take-off.
A qualifying clause is a very useful syntactic component in a rule statement. Compare the following rule statements:
|RS16.||Each Travel Insurance Application
must specify exactly one departure date.
|RS25.||Each Travel Insurance Application
that is for international travel
must specify at least one region.
|RS73.||The salutation specified for each passenger in each Travel Insurance Application
must be one of the name titles
listed in AS4590-2006.
Rule statement RS25 has the qualifying clause that is for international travel, while RS73 has the qualifying clause listed in AS4590-2006. By contrast, rule statement RS16 has no qualifying clause. Before we consider the various forms a qualifying clause can take, let's review their effects.
The qualifying clause in rule statement RS25 has the effect of restricting the Travel Insurance Applications to which the statement applies, namely only those for international travel. By contrast, rule statement RS16 applies to all Travel Insurance Applications.
The qualifying clause in rule statement RS73 does not restrict the Travel Insurance Applications to which the statement applies (like rule statement RS16, it applies to all Travel Insurance Applications) but does make the rule more stringent. For a Travel Insurance Application to comply with the rule stated in this rule statement, it can only specify name titles that are listed in the standard AS4590-2006. In other words, a Travel Insurance Application that specifies a name title that is not listed in the standard does not comply with the rule.
Note that the qualifying clause in rule statement RS25 is part of the subject (Travel Insurance Application) whereas the qualifying clause in rule statement RS73 is part of the predicate. If you want to restrict the instances in which the rule statement applies, include a qualifying clause in the subject, whereas if you want to make the rule more stringent, include a qualifying clause in the predicate.
What does a qualifying clause look like? The most common form consists of:
- that (unless the qualified term signifies an individual human being, in which case who is used instead)
- an intransitive verb phrase signifying a Boolean condition, such as is for international travel
- a transitive verb phrase followed by a noun phrase or literal signifying the object of that verb phrase, such as identifies each Travel Insurance Application, is made before 2pm.
When a qualifying clause starts with that is or who is, those words can sometimes be omitted, e.g.,
- for international travel can be used instead of that is for international travel
- made before 2pm can be used instead of that is made before 2pm
- booked on the same flight can be used instead of who is booked on the same flight.
There are exceptions: that is or who is cannot be omitted if the remainder of the clause is an adjective or passive participle (expired cannot be used instead of that is expired) or a noun phrase (a passenger on the same journey cannot be used instead of who is a passenger on the same journey). Nor can that is or who is be omitted if followed by not (not valid for any more journeys cannot be used instead of that is not valid for any more journeys).
Like prepositional phrases, qualifying clauses can be chained, e.g.,
- that has a balance less than $1000 (a shortened form of that has a balance that is less than $1000).
Again like prepositional phrases, qualifying clauses can be combined using and or or, e.g.,
- that is for a return journey or for a multi-stop journey
- that has a radius of 5km and is centred on the location of that registered club.
As we have seen, qualifying clauses can also use not, e.g.,
- that is not valid for any more journeys.
As we have seen, in a chained qualifying clause, the first noun phrase is qualified by another qualifying clause (in that has a balance that is less than $1000, balance is qualified by that is less than $1000). A noun phrase in a qualifying clause can also be qualified by a prepositional phrase, e.g.,
- (that is) shown by each guest of a registered club
- (that is) specified for any other high value item in that Travel Insurance Application.
Some other forms of qualifying clause can also be used. One form is useful when the term to be qualified is an indirect object of a verb phrase (i.e., follows a preposition), such as:
- runway, in aircraft lands on runway
- date, in Travel Insurance Application is made on date.
Using the common form of qualifying clause would result in such constructions as:
- that that aircraft lands on
- that that Travel Insurance Application is made on.
The alternative form — preferred by many — consists of:
- a preposition
- a determiner, most often that
- a term
- a verb.
- at which that aircraft lands
- on which that Travel Insurance Application is made.
Another form consists of:
- a term
- a predicate.
- whose age is less than 12 years.
Yet another form can be used when the verb phrase is negated. Consider rule statement RS294. If the only options are one-way journey, return journey, and multi-stop journey, the rule can be alternatively expressed as in RS295. Yet another alternative is to replace that is not by other than, as in RS296.
|RS294.||Each Flight Booking Request
that is for a return journey or a multi-stop journey
must specify exactly one return date.
|RS295.||Each Flight Booking Request
that is not for a one-way journey
must specify exactly one return date.
|RS296.||Each Flight Booking Request
other than for a one-way journey
must specify exactly one return date.
One more form involves a verb that either states or questions the truth of a proposition, such as state, ask, question, or check, as in "the witness stated that he had not seen the assailant clearly", "I asked if this were true", "She questioned whether he could have done it", or "The flight attendant checked that all passengers' seat belts were fastened". In each of these, the verb is separated from the following proposition by a conjunction (that, if, or whether). Note that:
This form of qualifying clause consists of:
- who (or that if the actor is an inanimate object, such as a system)
- the verb states, asks, questions, or checks
- the conjunction that, if, or whether
- a predicate.
- who checks that an aircraft door is disarmed.
To be continued...
In the next article in this series I will look at some more syntactic components that can be used in rule statements.
 The first of which is: Graham Witt, "A Practical Method of Developing Natural Language Rule Statements (Part 1)," Business Rules Journal, Vol. 10, No. 2 (Feb. 2009), URL: http://www.BRCommunity.com/a2009/b461.html
 Semantics of Business Vocabulary and Business Rules (SBVR), v1.0. Object Management Group (Jan. 2008). Available at http://www.omg.org/spec/SBVR/1.0/
The font and colour conventions used in these rule statements reflect those in the SBVR, namely underlined teal for terms, italic blue for verb phrases, orange for keywords, and double-underlined green for names and other literals. Note that, for clarity, these conventions are not used for rule statements that exhibit one or more non-recommended characteristics.
 A rule that defines a construct created or used by an organisation (or the industry within which it operates), or defines a property of such a construct, and which cannot therefore be contravened, by contrast with an operative rule.
 Graham Witt, "Writing Natural Language Rule Statements — a Systematic Approach — Part 21: The Syntax of Data Cardinality Rule Statements," Business Rules Journal, Vol. 15, No. 4 (Apr. 2014). URL: http://www.brcommunity.com/a2014/b757.html,
Graham Witt, "Writing Natural Language Rule Statements — a Systematic Approach — Part 22: The Syntax of Some Data Content Rule Statements," Business Rules Journal, Vol. 15, No. 5 (May 2014). URL: http://www.brcommunity.com/a2014/b762.html,
Graham Witt, "Writing Natural Language Rule Statements — a Systematic Approach — Part 23: The Syntax of Other Data Rule Statements," Business Rules Journal, Vol. 15, No. 6 (Jun. 2014). URL: http://www.brcommunity.com/a2014/b766.html,
Graham Witt, "Writing Natural Language Rule Statements — a Systematic Approach — Part 24: The Syntax of Activity Rule Statements," Business Rules Journal, Vol. 15, No. 7 (July 2014). URL: http://www.brcommunity.com/a2014/b769.html,
Graham Witt, "Writing Natural Language Rule Statements — a Systematic Approach — Part 25: The Syntax of Party Rule Statements," Business Rules Journal, Vol. 15, No. 8 (Aug. 2014), URL: http://www.BRCommunity.com/a2014/b773.html
 Statements of rules that prescribe or prohibit the content of data items representing spatial objects (points, line segments, polygons, other plane figures such as circles, or solid figures in 3-dimensional space), generally by reference to required relationships between those spatial objects and other spatial objects.
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