Period indicator: period_indicator

Syntax

period_indicator ( { op } )

Input parameters

op	the operand

Examples of valid syntaxes

::: period_indicator ( ds_1 ) period_indicator // (if used in a clause the operand op can be omitted)

Semantics for scalar operations

period_indicator returns the period indicator of a time_period value. The period indicator is the part of the time_period value which denotes the duration of the time period (e.g. day, week, month…).

Input parameters type

op

dataset { identifier <time_period> _ , identifier _* }
| component<time_period>
| time_period

Result type

result

dataset { measure<duration> duration_var }
| component<duration>
| duration

Additional Constraints

If op is a Data Set then it has exactly one Identifier of type time_period and may have other Identifiers. If the operator is used in a clause and op is omitted, then the Data Set to which the clause is applied has exactly one Identifier of type time_period and may have other Identifiers.

Behaviour

The operator extracts the period indicator part of the time_period value. The period indicator is computed for each Data Point. When the operator is used in a clause, it extracts the period indicator from the time_period value the Data Set to which the clause is applied.

The operator returns a Data Set with the same Identifiers of op and one Measure of type duration named duration_var. As for all the Variables, a proper Value Domain must be defined to contain the possible values of the period indicator and duration_var. The values used in the examples are listed at the beginning of this chapter “VTL-ML Time operators”.

Examples

Given the operand dataset DS_1:

Input DS_1 (see structure)

Id_1	Id_2	Id_3	Me_1
A	1	2010	10
A	1	2013Q1	50

Example 1

DS_r := period_indicator ( DS_1 );

results in (see structure):

DS_r
Id_1	Id_2	Id_3	duration_var
A	1	2010	A
A	1	2013-Q1	Q

Example 2

DS_r := DS_1 [ filter period_indicator ( Id_3 ) = "A" ];

results in (see structure):

DS_r
Id_1	Id_2	Id_3	Me_1
A	1	2010	10