CVR (CVR v0.1.0)

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Validates and generates Danish CVR-numbers.

Every Danish company is registered in CVR ("Det Central Virksomhedsregister"/"The Central Business Registry") with a unique CVR-number. This library can validate a given CVR-number according to the modulo-11 rule and generate random ones (if StreamData is present).

The modulo-11 rule

Like Danish CPR-numbers, CVR-numbers are generated according to a modulo-11 rule. For CVR-numbers, the first 7 digits is a sequential counter and the eighth digit is a control digit. This means that not all 8-digit numbers are valid CVR-numbers. For instance, 24256790 is a valid CVR-number, because the sum of multiplying each digit with a predefined weight divides evenly with 11. Similarly 24256791 is not a valid CVR number because the modulo-11 test does not hold.

Summary

Functions

generate()

Generate a random CVR-number.

valid?(cvr_number)

Validates whether a given CVR number is valid or not.

Functions

generate()

@spec generate() :: StreamData.t(pos_integer())

Generate a random CVR-number.

Requires StreamData. The generated CVR-numbers are guaranteed to be valid.

valid?(cvr_number)

@spec valid?(String.t() | integer()) :: boolean()

Validates whether a given CVR number is valid or not.

This function accepts both integers and strings as inputs. The strings must either contain a number, or a number preceeded by either "DK" or "DK-". The "DK-12345678" format is commonly used in systems that can handle different company registration IDs from different countries.

Usage

iex> CVR.valid?("DK24256790")
true

iex> CVR.valid?("DK-24256790")
true

iex> CVR.valid?(24256790)
true

iex> CVR.valid?("Not a number")
false

iex> CVR.valid?("DK-24256791")
false

iex> CVR.valid?(24256791)
false

iex> CVR.valid?(10000000)
false