Model ValidationErrors

This model records all validation errors, indexed by the Index of the event sequence.

The model should always be empty. It is checked using a Calculation Theory before importing events into the Event store.

If a ValidationError occurs at any historical index, no further events can be imported.

Validation logic

Validation checks are performed on every event before it is imported.

Typical validations include: - Required fields (e.g. option, charity, donation must be known) - Value ranges (e.g. fractions must be between 0 and 1, amounts must be positive) - Consistency checks (e.g. fractions must add up to 1) - Uniqueness (e.g. new options must not be duplicates) - Referential integrity (e.g. referenced donations and charities must exist)

If any validation fails, a validation error is recorded at the corresponding index, and event import is halted.