Dimension and Default Unit 

A numeric attribute can be defined as having an associated physical dimension, so that each numeric value you enter also includes a unit of measure chosen from the list of units applicable to that dimension.

MDM currently has built-in support for over 70 different physical dimensions and over 750 different units of measure. In addition, MDM is able to convert between different units, for proper sorting of numeric values with different units within a list.

The Dimension and Default Unit properties are drop-down lists. To specify the Dimension for a numeric attribute, select from the drop-down list of physical dimensions (figure below). To specify the Default Unit, if any, to be used by MDM for new data values, select from the drop-down list of units of measure corresponding to the selected dimension. The default value for both Dimension and Default Unit is None.

Physical dimensions and units of measure make it easy to enforce data integrity, since units of measure must be selected from a predefined list of units rather than typed in by the user as a text string.

You must specify a unit of measure for each numeric value if a physical dimension is defined for the attribute.

Just as with a numeric attribute, the physical dimension is optional for either or both coupled dimensions of a coupled numeric attribute.

When you change the physical dimension for a numeric attribute that already has data values assigned to it from None or from another dimension, MDM does not allow you to select None as the Default Unit and makes special use of the unit you specify to automatically repopulate the unit part of each existing attribute value. To set the Default Unit to None, first save the attribute with a Default Unit, then change the Default Unit to None and save it again.