@Override
	public String getSingleRowKeyColumnNotContainedInAssociationKey() {
		String nonKeyColumn = null;

		for ( String column : getRowKeyColumnNames() ) {
			if ( !isKeyColumn( column ) ) {
				if ( nonKeyColumn != null ) {
					// more than one column which is not contained in the association key; thus rows of this
					// association will be represented by DBObjects rather than single String, int etc. objects
					return null;
				}
				else {
					nonKeyColumn = column;
				}
			}
		}

		return nonKeyColumn;
	}
@ Override public String getSingleRowKeyColumnNotContainedInAssociationKey ( ) { String nonKeyColumn = null ; for ( String column : getRowKeyColumnNames ( ) ) { if ( ! isKeyColumn ( column ) ) { if ( nonKeyColumn != null ) { return null ; } else { nonKeyColumn = column ; } } } return nonKeyColumn ; }
Returns the name of the single row key column which is not a column of this key itself, in case such a column
exists.
<p>
If e.g. an association key contains the column "bankAccounts_id" and the row key columns are "bankAccounts_id"
and "owners_id", this method will return "owners_id". But if the row columns were "bankAccounts_id", "owners_id"
and "order", {@code null} would be returned as there were more than one column which are not part of the
association key.

@return the name of the single row key column which is not a column of this key itself or {@code null} if there
is either no or more than one such column.