Each dynamic property is actually a derived property that uses the atg.repository.dp.MapBackedAlias derivation method to store and retrieve values. The property values are actually stored in properties called backing map properties.
If the addBackingMapPropertiesOnStartup property of the repository component is true, a set of four backing map properties is automatically generated for each item descriptor in the repository when it starts up. The backing map property used to hold a given value is determined by the value’s repository data type:
atgDynamicPropertyMapString– Holdsstringvalues.atgDynamicPropertyMapBigString– Holdsbigstringvalues.atgDynamicPropertyMapDouble– Holdsfloatanddoublevalues.atgDynamicPropertyMapLong– Holdsint,date,enumerated,timestamp,boolean, andlongvalues.
So, for example, if you create a product item property named weightInGrams that holds float values, these values would be stored as atgDynamicPropertyMapDouble properties of the product item type.
The addBackingMapPropertiesOnStartup property is set to true by default for the product catalog and content management repositories. A set of backing map properties is generated for each item descriptor in these repositories. If you do not want backing map properties to be generated for a specific item descriptor, use an attribute tag to set the skip-backing-map-generation attribute to true in the descriptor definition. For example:
<item-descriptor name="media-external" ...>
<attribute name="skip-backing-map-generation" value="true"/>
</item-descriptor>
