Get Default dimension values in Ax 2012

public DimensionValue GetDimension(DimensionDefault defaultDimension,SAB_DimAttrBackingEntityMapping     dim)
{

    select recid from dimensionAttributeValueSet
        where dimensionAttributeValueSet.RecId == _defaultDimension
    join DisplayValue from dimensionAttributeValueSetitem
        where dimensionAttributeValueSetitem.DimensionAttributeValueSet == dimensionAttributeValueSet.RecId
    join recid from dimensionAttributeValue
        where dimensionAttributeValue.RecId == dimensionAttributeValueSetitem.DimensionAttributeValue
    join recid,Name from dimensionAttribute
        where dimensionAttribute.RecId == dimensionAttributeValue.DimensionAttribute
            && dimensionAttribute.SAB_BackingEntityMapping == _dim;

    return dimensionAttributeValueSetitem.DisplayValue;
}


sampleTmp.BussinessUnit              = this.GetDimension(salesline.DefaultDimension,SAB_DimAttrBackingEntityMapping::BusinessUnit);
  sampleTmp..Department               = this.GetDimension(salesline.DefaultDimension,SAB_DimAttrBackingEntityMapping::Department);