| 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 2.6: 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 2.1.1 and Output 2.3.2 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.
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