The BOM Procedure

Missing Values in the Input Data Sets

The following table summarizes the treatment of missing values for variables in the input data sets used by PROC BOM.

Table 3.6: Treatment of Missing Values in the BOM Procedure

Data Set

Variable

Value Used/Assumption Made/Action Taken

Part Master

ID

Missing, if Part is not missing;

   

otherwise ignored

 

LeadTime

0, if Part is not missing;

   

otherwise ignored

 

Part

Value ignored

 

QtyOnHand

0, if Part is not missing;

   

otherwise ignored

 

Requirement

Ignored if Part is missing;

   

1, if Part is not missing and the item identified by the Part variable is an end item;

   

otherwise, the value is determined by the procedure

Product Structure

Component

Value ignored

 

Factor

0, if corresponding Component variable is not
missing;

   

otherwise ignored

 

Offset

0, if corresponding Component variable is not
missing;

   

otherwise ignored

 

Parent

Input error: procedure stops with error message, if this is the first observation;

   

otherwise, the value of the Parent variable in the previous observation

 

Quantity

1, if corresponding Component variable is not
missing;

   

otherwise ignored

 

RID

Missing, if corresponding Component variable is not missing;

   

otherwise ignored


Note that in the Product Structure data set, a missing value is allowed for the Parent variable only when two or more consecutive observations contain product structure records with the same parent item (see Output 3.1.1 and Output 3.3.2 as examples). In the Part Master data set, if the Part variable is missing, the values for the ID , LeadTime , QtyOnHand , and Requirement variables are ignored by the procedure. If the Part variable is not missing but the Requirement variable value is missing, the gross requirement of the item identified by the Part variable is assumed to be 1 if the item in question is an end item. Otherwise, the gross requirement of this item is determined based on the dependent demand process. See the section Summarized Parts Data Set for details about the dependent demand process.