Validation rules can be used to validate data for properties before they are stored. There may be predefined system validation rules and user defined validation rules for each property.

All validation rules for the property that are defined (both system and context specific) are checked when value is modified. If one of the validation rules fail the property value does not validate.

Note: Validation rules are checked only when data is stored. Changing existing validation rules or creating new validation rules does not re-check already stored data. Therefore you might have data in your system that is not valid according to the current validation rules.

Validation rules are mainly intended to help the user when data is entered manually, usually data is imported from other systems (via files or online connection) validation rules do not make sense since you usually want the original data in your system. Additionally, checking validation rules takes time to process - so when huge amounts of data are stored it is wise not to have validation rules in the property setting context of the feature that stores this data.

All validation rules for feature data or observation data can be enabled or disabled together for a feature.