4.5.8.11. 3DCityDB metadata

The 3DCityDB stores database-specific metadata with every city object using the columns LAST_MODIFICATION_DATE, UPDATING_PERSON, REASON_FOR_UPDATE and LINEAGE of the CITYOBJECT table. In order to make these metadata properties available in filter expressions, the 3DCityDB ADE injects them into the CityGML core:_CityObject feature.

Table 4.14 3DCityDB ADE properties for accessing database-specific metadata information.

ADE property (injected into core:_CityObject)	Data type	Column of the CITYOBJECT table
citydb:lastModificationDate	xs:string	LAST_MODIFICATION_DATE
citydb:updatingPerson	xs:string	UPDATING_PERSON
citydb:reasonForUpdate	xs:string	REASON_FOR_UPDATE
citydb:lineage	xs:string	LINEAGE

The properties can also be used in filter expressions. For instance, the query below fetches all bridges that have been modified in the database after 2018-01-01.

<query>
  <typeNames>
    <typeName>brid:Bridge</typeName>
  </typeNames>
  <filter>
    <propertyIsGreaterThan>
      <valueReference>citydb:lastModificationDate</valueReference>
      <literal>2018-01-01</literal>
    </propertyIsGreaterThan>
  </filter>
</query>