Help:Change propagation/Property change propagation

Locked property on a change awaiting job execution

Shows progress information about about the property change propagation

Missing value assignments while type change propagation is underway

A selected list (see $smwgChangePropagationWatchlist) of declarative properties are watched and when altered will trigger a change propagation event.

For example, the change of a property's datatype will initiate a change propagation process on all dependent entities that have a value assigned for the altered property and will temporary (after the change) appear with an unassigned value while the job queue is working its way through the backlog. Depending on the size and rate of executable jobs, the update may take a moment before all entities can display the newly assigned type with value (e.g. recomputing the value, changing its display characteristics etc.).

The reason for this process is that each datatype is described by certain display characteristics (e.g datatype "Date"Holds particular points in time vs. datatype "URL"Holds URIs, URNs and URLs) and value constraints and with that it influences a property's specification therefore a change propagation ensures that an altered property notifies all entities with an assigned value to be updated in due time.

The smw.changePropagationUpdate1 is used solely for the update of properties in order to distinguish it from other change propagation jobs and to make an estimation of remaining jobs.

See also

• Help page on properties and types
• Help page on change propagation
• Help page on configuration parameter $smwgChangePropagationWatchlistSets the properties that are relevant for property change propagation
• Help page on configuration parameter $smwgChangePropagationProtectionSets whether property pages are protected from editing while a property change propagation is being processed
• Help page on special property "Change propagation"Holds the new property specification of a property or category page