p key or map
 value.

 <p> To override mappings at multiple levels of embedding, a dot (".")
 notation form must be used in the <code>name</code> element to indicate an
 attribute within an embedded attribute.  The value of each identifier
 used with the dot notation is the name of the respective embedded
 field or property.

 <p> If <code>AttributeOverride</code> is not specified, the column
 is mapped the same as in the original mapping.

 <pre>
    Example 1:

    &#064;MappedSuperclass
    public class 