Hi,
yes! SDBExplorer supports you to know the domain size by viewing Domain property.To view domain property -
Choose Property option from the right click on the domain.
This will show you size of attribute - value pair and total number of attributes.
In total you can calculate the domain size.
for more detail -
http://www.sdbexplorer.com/documentation/simpledb--how-to-check-domain-property.htmlregards-
Udit