Abstract head of the substitution group for program bases: the objects a design wasprepared from, such as ground models, requirement sets, governing standards andcalculation inputs. A basis is evidence, not intent and not constraint: it is whatthe designer relied on, and a design cites it through basisRef.
Database handle for the object. It is of XML type ID, so is constrained to beunique in the XML document within which it occurs. An external identifier for the object inthe form of a URI may be constructed using standard XML and XPointer methods. This is doneby concatenating the URI for the document, a fragment separator, and the value of the idattribute.
Source
<element abstract="true" name="AbstractProgramBasis" type="diggs:AbstractProgramBasisType" substitutionGroup="diggs:AbstractProgramModule"><annotation><documentation>Abstract head of the substitution group for program bases: the objects a design was prepared from, such as ground models, requirement sets, governing standards and calculation inputs. A basis is evidence, not intent and not constraint: it is what the designer relied on, and a design cites it through basisRef.</documentation></annotation></element>