Date Time Vocabulary BusinessUsage Guidelines
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Date-Time Vocabulary
Annex C – Business Usage Guidelines
(Informative)
C.1 Introduction
Developers of business vocabularies need to understand how to employ the Date-Time
Vocabulary (DTV). The normative clauses of this specification contain both concepts intended
for business use, and concepts that describe the complex technical details of time concepts.
Which Date-Time noun concepts provide the right foundations for business vocabularies and
business rules? This Annex answers that question in two ways: by a discussion of and examples
of "calendar expressions", and by inventorying the Date-Time noun and verb concepts
recommended for business use.
C.2 Calendar Expressions
Business speech commonly includes references such as "every Monday at noon for 2 hours",
"the fourth Thursday of each November", "October 1 through September 30", and "the first
Tuesday after the first Monday in November". For the purposes of this annex, complex
combinations of calendar dates, such as these examples, are called "calendar expressions". This
section shows how calendar expressions are formalized using DTV concepts.
Calendar expressions may appear in SBVR Definition, Necessity, and Possibility statements.
The normative portions of DTV define many concepts that may be combined to formalize these
expressions. Principal among these are calendar-defined noun concepts (such as "Monday" and
"November") which identify time intervals, and verb concepts that relate time intervals to each
other by containment (as calendar months contain calendar days) and by temporal order.
The number and variety of possible calendar expressions is unlimited, so it is not possible to
describe how to formalize every such expression. Instead, the table below gives examples of
common forms, with the expectation that readers can easily adapt the examples to their needs.
Calendar Expression
Example DTV and SBVR Formalization
A team must be scheduled every Monday at
noon for 2 hours.
A team meeting must be scheduled for each
Monday at noon for 2 hours.
'Thanksgiving day' defined as "the fourth
Thursday of each November"
Thanksgiving day
Definition: the fourth of the Thursdays that are in
a given November
'default contract term' defined as "October 1
through September 30"
default contract term
Definition: time interval that is from October 1
through September 30
The Annual General Meeting (AGM) must be
schedule on the first Tuesday after the first
Monday in November
The AGM for a given Gregorian year must be
scheduled on the first of the Tuesdays that are after
the first of the Mondays that are in the November of
the Gregorian year.
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Calendar Expression
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Example DTV and SBVR Formalization
"the cancellation period is the three days after
the contract signing", as used in a definition
of a verb concept 'contract has cancellation
period'
contract has cancellation period
Definition: the cancellation period of the contract
is the 3 days following the contract
signing of the contract
'contract term' defined as "from the contract
signing to the contract termination"
contract term
Definition: time interval that is from the signing of
a contract to the termination of the
contract
'contract initial stub' defined as "contract
signing through the end of the year"
contract initial stub
Definition: time interval that is from the signing of
a contract through the time interval
that ends the calendar year of the
signing of the contract
C.3 Date-Time Business Terms
Business vocabularies can build upon any of the Date-Time concepts, but many DTV concepts
deal with intricacies of time and calendars that are not relevant to businesses. Those concepts
that are intended for business use are summarized here for the convenience of DTV users.
C.3.1 Durations and Time Units
Durations are amounts of time, such as the length of a meeting. Durations may be specified by
literal amounts, such as "3 weeks", or "10 minutes", using these well-known time units: day, hour,
minute, month, second, week, and year. Durations may also be specified as the lengths of time
periods (see section C.3.2, below).
Businesses should build upon the term 'duration' for all concepts whose meaning is an amount of
time. When a business requires measuring time in specific units, an SBVR Definition or
Necessity can specify the constraint. For example, EU-Rent defines a "rental hour" as "duration
that has the time unit 'hour'".
Any two durations may be compared using verb concepts is equal, is greater than / is less
than, and is greater than or equal / is less than or equal. Duration arithmetic is enabled by
plus and minus verb concepts, and by a number times duration verb concept.
C.3.2 Time Periods
Businesses often need to reference time periods, which are places in time. For example, EU-Rent uses
the term 'rental period' to mean a time period from when a rental starts to when it finishes.
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DTV defines a number of standard time periods whose duration is one of the standard time units listed
above, in section C.3.1. DTV distinguishes between calendar-based time periods and arbitrary time
periods. Calendar-based time periods start and end according to a clock or calendar: calendar day,
calendar week, calendar month, calendar year, second of day, minute of day, hour of day.
Arbitrary time periods are periods whose duration is a standard time unit and that start at any time: day
period, week period, month period, year period.
Businesses should use 'time period' for most purposes. The other concepts narrow the meaning of 'time
period' to specify periods of particular time units or calendar alignments. Use those only when the
narrowing of meaning is intended.
Do not confuse time units with time periods; the former are about amounts of time (e.g. specifying the
length of a contract), while the latter are about locations in time (e.g. the period from the start of a
contract to its end). For example, a contract that has duration "3 months" might take place during three
calendar months starting at the beginning of May.
A date or calendar date is a calendar reference, such as "July 17, 2015", that means a calendar
day. A time of day (e.g. "12:45:16") means a second of day, minute of day, or hour of day
depending upon its granularity. A date time or date and time is the combination of a date and a
time of day. Dates can incorporate the usual English month names (January, etc.) and weekday
names (Monday, etc.) You can use a calendar reference wherever you mean a time period. For
example, EU-Rent defines the term 'transfer date' (the date when a car is moved among EU-Rent
branches) as a category of DTV 'date'.
There are many ways to compare or combine time periods, as shown in Table C.1. To save space in the
table, the roles of the verb concepts are abbreviated: t indicates a role that can be filled by a time
period 1 (e.g. "rental period") or a calendar reference (e.g. "July 17, 2015"). Multiple synonymous forms
are listed for some verb concepts.
Table C.1: Verb Concepts for Time Periods
Time Period Verb
Concepts
1
Informal Description
Example
(‘Necessity’ definitional rules)
t begins before t
The start of one time period is
before or the same as the start of
the other.
The contracted period of a rental
begins before the actual pick-up date
time of the rental.
t ends after t
The end of one time period is the
same or after the end of the other.
The closure date-time of a rental ends
after the actual return date time of the
rental.
Technically, these verb concepts relate time intervals, but time periods are more relevant to business users.
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Time Period Verb
Concepts
Informal Description
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Example
(‘Necessity’ definitional rules)
t finishes t
The first time period starts
after the second time period,
but ends with the second time
period.
The scheduled return date time
of a rental finishes the scheduled
rental period of the rental.
t finishes after t
The two time periods overlap,
but the end of one time period
is later than the end of the other.
The chargeable period of a late-return
rental finishes after the contracted
period of the rental.
t finishes with t
The two time periods end
together, but either may start first.
The scheduled return date time of a
late-return rental finishes with the
contracted period of the rental.
t is t
t equals t
The two time
same.
The chargeable period of an earlyreturn rental is the contracted period
of the rental.
t is after t
t is before t
t follows t
t precedes t
t is followed by t
One time
another.
t is between t and t
The first time period is after
the second and is before the
third.
The open period of an advance rental
is between the booking period of the
rental and the closure period of the
rental.
t includes t
t is part of t
t is within t
One time period is contained
within or is the same as another.
The chargeable period of a rental
is a part of the open period of the
rental.
t is proper part of t
One time period is entirely
contained within another.
The opening hours of a branch
are a proper part of the working
hours of the branch.
t meets t
One time period ends just as
another starts.
The open period of an advance rental
meets the closure period of the rental.
t overlaps t
Some part of one time
is within the other.
The time period of a breakdown of
a car may overlap the rental period
of the car.
periods are the
period is after
period
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The open period of an advance rental
is after the booking period of the
rental.
Date Time Vocabulary BusinessUsage Guidelines
Time Period Verb
Concepts
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Example
(‘Necessity’ definitional rules)
Informal Description
t starts t
The first time period starts at
the same time as the second time
period, but ends before the
second time period ends.
The actual pick-up date time of a
rental starts the chargeable
period of the rental.
t starts before t
The two time periods overlap,
and the start of the first time
period is earlier than the start of
the second time period.
The working hours of a branch starts
before the opening hours of the
branch.
t starts with t
The two time periods start
together, but either may end first.
The chargeable period of a rental
starts with the actual pick-up datetime of the rental.
t to t
A time period from the start of
the first time period to the start
of the second one.
The rent period of an apartment lease
is the first day of a calendar month1 to
the first day of the calendar month2
that follows the calendar month1.
t through t
The smallest time period that
includes both of them.
The chargeable period of a short-term
apartment rental is the first calendar
month of the rental through the final
calendar month of the rental.
Table C.2 lists verb concepts that relate durations and time periods. In this table, d represents a
duration, and t represents a time period.
Table C.2: Verb Concepts that Relate Durations and Time Periods
Verb Concepts that
Relate Durations and
Time Periods
t finishes d after t
Informal Description
The first time period ends d after
the end of the second time period.
Example
The grace period of a rental
finishes 30 minutes after the
scheduled return date-time of
the rental.
t is d after t
t is d before t
The first time period starts or ends
d after or before the start of the
second time period.
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The late period of a rental is 1 day
after the scheduled return datetime of the rental.
Date Time Vocabulary BusinessUsage Guidelines
Verb Concepts that
Relate Durations and
Time Periods
Informal Description
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Example
t is the d following t
The first time period has
duration d and immediately
follows the second time period.
The grace period of a rental is
the 30 minutes following the
scheduled return date-time of
the rental.
t is the d preceding t
The first time period has
duration d and immediately
precedes the second time period.
The tax look-back period is the 2
years preceding the date of death.
t starts d before t
The first time period starts d
before the start of the second time
period.
The pre-game coverage period
starts 1 hour before the start of the
game.
t finishes d after t
The first time period ends d after
the end of the second time period.
The TV coverage period finishes
30 minutes after the end of the game.
d of t
The amount of time in the time
period.
The base price of a rental is
calculated using the duration of the
chargeable period of the rental and
the rental rates of the car group of
the rental.
C.3.3 Occurrences and Time
Occurrences are real events, activities, situations, or circumstances that actually happen at
some time. Use 'occurrence' when referring to individual events (etc.), such as the actual drop-off
of a rental. Use 'situation kind' (below) for rules and vocabulary concepts about events (etc.) that
may or may not occur, such as potential rentals.
DTV presents, per Table C 4.3, several verb concepts that relate occurrences to time. In the
following tables, the symbols o represents the concept occurrence, t means time period or
interval, and d means duration. To save space, verb concepts that are paired (with "start" and
"end" versions) are described together.
Table C.3: Occurrences and Time
Relationships between
Occurrences and Time
Informal Description
o ends at t
o starts at t
The occurrence starts or ends simultaneously with the time
o ends after t
o starts before t
The occurrence starts before /ends after the time
period starts / ends.
o for t
The occurrence happens exactly during the time
period.
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period.
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Relationships between
Occurrences and Time
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Informal Description
o is between o and o
The first occurrence happens between the other two.
t is the d preceding o
t is the d following o
The time
o starts d after o
o ends d after o
The first occurrence starts / ends duration d before / after the second
occurrence starts / ends.
t starts d before o
t ends d after o
The time
o occurs d before t
o occurs d after t
The occurrence starts / ends duration d after / before the time
interval ends / starts.
d of o
o lasts d
The duration of the occurrence.
o overlaps o
o while o
The first occurrence starts before the second occurrence starts, and
ends before the second occurrence ends.
o precedes o
The first occurrence happens before the second one.
o through o specifies t
The time period extends from the start of the first occurrence through
the end of the occurrence.
t through o specifies t
The second time period extends from the start of the first time
through the end of the occurrence.
o throughout t
The occurrence happens during the time
or end later than the time period.
o to o specifies t
The time period extends from the start of the first occurrence up to,
but not including the start of the second occurrence.
t to o specifies t
The second time period extends from the start of the time
but not including the start of the occurrence.
o to t specifies t
The second time period extends from the start of the occurrence up to,
but not including the start of the first time period.
o within t
The occurrence happens some (possibly shorter) time during the time
period.
period has duration d, and is immediately before or after the
occurrence.
interval starts / ends duration d before / after the
occurrence starts / ends.
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interval
period, but may start earlier
period up to,
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C.3.4 Situation Kinds and Time
Situation kinds are events, activities, situations, or circumstances that may or may not happen,
and may happen multiple times. For example, the business concept 'rental booking', defined as
"acceptance by EU-Rent of a request from a renter for an advance rental" implicitly is a situation
kind that happens multiple times. The situation kind 'rental booking' itself has no unique time,
but its occurrences each happen at specific times.
The verb concept 'situation kind has occurrence' defines the relationship between situation
kinds and occurrences. A situation kind can have zero, one, or many occurrences.
It can be difficult to distinguish between situation kinds and occurrences, because many situation
kinds have just one occurrence. These are called individual situation kinds. For example, a
business concept defined as "the incorporation of EU-Rent" may have just one occurrence. For
practical purposes, the distinction between individual situation kinds and their occurrences is
often ignored. Most of the verb concepts listed in Table C.3 are also defined for individual
situation kinds.
Table C.3 uses the symbols s for situation kinds and t for time period in verb concepts that relate
situation kinds to time.
Table C.3: Situation Kinds and Time
Relationships between
Situation Kinds and Time
Informal Description
s ends before s
All occurrences of the first situation
of the second situation kind.
s has o
The occurrence is one (of possibly many) instances of the situation
s has o after t
The occurrence is the first occurrence of the situation
time period.
kind after the
s has o before t
The occurrence is the last occurrence of the situation
time period.
kind before the
s is between s and s
All occurrences of the first situation kind start after the end of all
occurrences of the second situation kind, and end before or with the start of
all occurrences of the third situation kind.
s occurs for t
The situation
period.
t of s
t is the smallest time
kind.
s starts before s
All occurrences of the first situation kind starts before the start of every
occurrence of the second situation kind.
s throughout t
The situation kind has an occurrence that occurs throughout the time
period, and may start before or end after the time period.
kind end before every occurrence
kind.
kind has an occurrence that occurs for exactly the time
period that contains all the occurrences of the situation
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Relationships between
Situation Kinds and Time
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Informal Description
s while s
Every occurrence of the first situation
the second situation kind.
s within t
The situation
time period.
kind overlaps some occurrence of
kind has an occurrence that occurs during some part of the
C.3.5 Indexical Time Concepts
Indexical time concepts are concepts that are defined relative to some reference time, such as
"the next day after the rental drop off date". Table C.5 lists the DTV indexical time verb
concepts. All are defined with respect to some reference time period that should be made explicit
in the definition or rule that uses them. The table uses the symbol t to mean a time period or
interval.
Table C.5: Indexical Time Verb Concepts
Indexical Verb Concepts
Time Adjective
t is past
past
The time
period is before some reference time period.
t is current
current
The time
period includes the reference time period.
t is future
future
The time
period is after some reference time period.
Informal Description
The indexical time intervals are not listed here because there are so many of them. See the
detailed list in DTV clause 15.3.
To keep the indexical time intervals straight, they are named using the regular pattern "<time
adjective> <time frame>". The time adjectives are listed in Table C.5. The time frames are
"day", "hour", "month", "week", "year", and "time". Each of these time frames means a time
period of the corresponding length. The time frame called "time" is any time period. For
example, "current day" means a calendar day that includes some reference time period, "past
year" means a calendar year that is before some reference time period, "future time" means a
time interval that is after some reference time interval.
C.3.6 Tense and Aspect
Regulations, contracts, and business policies often reference the future or past with respect to
some time (e.g. the inception of a contract), and often need to distinguish between the
continuation of a situation (such as the ongoing rental of a car) versus the completion of one
(such as the completed rental of a car) as of some time. In English, verb tense indicates event
time frames, and verb aspect identifies the completion status of situations. Table C.6 summarizes
the DTV verb concepts for tense and aspect, using the symbol x to mean either 'situation kind' or
'occurrence' because many of these concepts apply to both.
Verb aspect can be confusing, because a situation or occurrence can be continuing or
accomplished, or both, or neither. Table 7.1 in clause 7.12 gives business examples of the
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twelve possible combinations of the three tenses and 4 aspects. The table at the end of clause
16.9 shows how these twelve combinations are formed from the verb concepts in Table C.6. All
these verb concepts are defined with respect to some reference time period that should be made
explicit in the definition or rule that uses them.
Table C.6 uses the symbols x to mean either an occurrence or a situation kind, and t to mean a
time period or interval.
Table C.6: Language Tense and Aspect
Language Tense and
Aspect
Informal Description
Example
(‘Obligation’ behavioral rules)
x is accomplished
An occurrence (or all
occurrences of a situation kind)
has reached a point of perfection at
some reference time period.
A renter who has damaged a
rented car must pay the insurance
deductible of the rental of the
rented car.
x is accomplished in
t
An occurrence (or all
occurrences of a situation kind)
has reached a point of perfection at
some time within the time period.
A customer who has purchased a
product in a holiday sales period
must not apply for a refund for the
product.
x is continuing
An occurrence (or all
occurrences of a situation kind)
is ongoing at some reference time
period.
A guest who is occupying a hotel
room must not entertain visitors in
the hotel room.
x is both continuing
and is accomplished
An occurrence (or all
occurrences of a situation kind)
that is ongoing but has reached a point
of perfection at some reference time
period.
A guest who has been renting a
hotel room must pay for the hotel
room.
x is in the past
An occurrence (or all
occurrences of the situation
kind) occurs in the past with respect to
some reference time period..
Each product promotion that is in
the past must be reported in the
accounts of the quarter that
includes the end date of the
product promotion.
x is current
An occurrence (or all
occurrences of the situation
kind) occurs for some reference time
period.
Each product promotion that is
current must have weekly status
reports.
x is in the future
An occurrence (or all
occurrences of the situation
kind) occurs in the future with respect
to some reference time period.
Each product promotion that is in
the future must be authorized by a
senior manager.
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C.3.7 Schedules
Schedules are combinations of times and situation kinds that are planned to occur at the times.
Regular schedules repeat regularly, whereas ad hoc schedules list irregular times and
matching situation kinds. Examples of schedules include airline schedules, meeting schedules,
and so forth.
A regular schedule is defined by a start time, a recurrence count, a recurrence duration,
and a situation kind. The situation kind is planned to occur at the start time, and to repeat once
per recurrence duration for the indicated count. A regular schedule can have an initial stub and a
final stub, which each identify a situation that should occur at a time before or after the
repeating part of the regular schedule.
An ad hoc schedule is defined by a set of schedule entries, each of which has a situation
kind and a time interval. Each situation kind is planned to occur at the corresponding time
interval.
Both kinds of schedule have an earliest time (the earliest time an occurrence is planned), a
latest time (the latest time an occurrence is planned), and a time span (the time interval that
covers the entire schedule).
DTV clause 16 gives the details.
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