This operator creates an output attribute on the basis of a given SQL definition (Parameter SQL_String). The definition must be well-formed SQL defining how values for the output attribute are computed based on one of the attributes in TheInputConcept. To refer to the attributes in TheInputConcept, the names of the BaseAttributes are used--and not the names of any Columns. For example, if there are two BaseAttributes named "INCOME" and "TAX" in TheInputConcept, this operator can compute their sum if SQL_String is defined as "(INCOME + TAX)". Since the operator must resolve names of BaseAttributes, it cannot be used if there are two or more BaseAttributes in TheInputConcept with the same name.
TheTargetAttribute is needed to have a blueprint for TheOutputAttribute. The operator ignores TheTargetAttribute, except that it uses the relational datatype of its column to specify the relational datatype for the column of TheOutputAttribute.
|TheTargetAttribute||BA||IN||inherited; specifies datatype|