Direct Replenishment in Business Central includes two date fields on each planning line: due date and order date (supply date). These two fields determine whether a planning line is forward planned or backward planned. If you enter an order date, the system forward plans from that date. If you enter a supply date, the system backward plans from that date.
You control which date the system uses through date triggers in your suggest-quantity-to-order template. You can set triggers on zero inventory, safety stock, and reorder point, and you can decide for each whether the system calculates forward or backward from that point. You can also set a fixed date as a fallback when no trigger fires.
The triggers are evaluated in order, so the first one that fires decides the date for that line. This means a line can be backward planned from a zero breach even when an earlier safety stock breach would have produced a different result. The triggers work in sequence and do not combine the way full MRP would.
How due date and order date work in Direct Replenishment
When you calculate in the Direct Replenishment worksheet, the system finds the items that need replenishment and suggests a quantity to order based on your setup. Each line gets two date fields you can work with: an order date (also referred to as supply date) and a due date.
The logic is straightforward. If you enter an order date, for example sometime in August or September, the line is forward planned from that date onwards. If you enter a supply date instead, the line is backward planned from that date and back. When you carry out the planning, one approach gives you a due date and the other gives you a start date.
You can set these dates manually on each line if you want full control. The due date column shows you which lines ended up backward planned and which ended up forward planned.
Using date triggers in the suggest-quantity-to-order template
Instead of entering dates by hand, you can let a date template suggest them. The template can hold several date triggers, and you define the order in which they are checked.
A typical setup checks the conditions in this sequence:
- Zero inventory: If the projected inventory drops below zero, the system calculates backwards from that point.
- Safety stock: If the zero trigger does not fire, the system checks for a safety stock breach and calculates forward from that point.
- Reorder point: If neither of the above fires, the system looks at the reorder point and calculates forward from that point.
- Fixed date: If none of the triggers fire, you can set a specific date that the system enters on the line. For example, you might set it to 17 November.
With the more complex templates, you can combine these triggers in one template and decide the calculation direction for each. The result is that some lines come out backward planned and some forward planned, all from the same run, depending on which trigger fired for each item.
Automatic quantity and date suggestions
If your template has the auto-run option enabled for suggest quantity to order, the system fills in both the quantity and the date automatically when you calculate. You can see this in the template settings: scroll to the right and you find the check mark for auto-run suggest quantity to order, linked to a quantity-to-order template.
The quantity comes from the triggers on ending inventory. For example, reorder point plus reorder quantity, calculated backwards from zero, with order modifiers applied. If you run the suggest-quantity-to-order action again, the values update.
Reorder point template produces more lines
If you switch to a template that triggers below the reorder point, you get more lines in the worksheet. This template fires whenever the projected inventory drops below the reorder point, so it catches items that are not necessarily breaching zero or safety stock. You end up with a lot more dates and quantities filled in automatically.
How the trigger order affects the result
Because the triggers are evaluated in order, the first one that fires decides the date, and the planning stops looking at the later triggers. This can produce a result that differs from what full MRP would do.
Take a lamp item as an example. The line says backward plan from 21 May. Looking at the dates, the item has a zero breach on 21 May, so according to the logic the system checks “do we go below zero” first and calculates backwards from there. It did exactly what it was asked to do.
The item also has a safety stock breach two months earlier, and the template could have calculated forward from that breach. But the planning never reached that trigger, because the zero breach fired first. In the graphical inventory profile you can see the full picture for this item:
- Reorder point: 68
- Safety stock: 34
- On 20 March the inventory drops below the reorder point
- On 25 March it drops below safety stock
- On 21 May it drops below zero
Because the zero trigger has priority, the system uses 21 May and backward plans from there, even though earlier breaches existed. This is the best Direct Replenishment can do with backward and forward planning. Full MRP would have handled the multiple breaches differently.
What to do in practice
The takeaway is that you need to think through how you set up your templates. The order of your triggers and the calculation direction you assign to each one directly determines whether each line is forward or backward planned, and which date it lands on.
When you accept the action messages and carry out the planning, some lines come out backward planned and some forward planned, depending on what was entered in the order date and supply date columns. You can always override those columns manually if a specific line needs a different date.
Q&A
What is the difference between order date and supply date in Direct Replenishment?
If you enter an order date, the line is forward planned from that date onwards. If you enter a supply date, the line is backward planned from that date and back. The due date column shows which lines ended up forward or backward planned.
How do date triggers work in the suggest-quantity-to-order template?
You define triggers on zero inventory, safety stock, and reorder point, and assign a calculation direction to each. The system checks them in order, and the first trigger that fires decides the date for that line. A common setup calculates backwards from a zero breach, forward from a safety stock breach, and forward from a reorder point breach, with a fixed date as a fallback.
Why does a line use a later breach date instead of an earlier one?
Because the triggers are evaluated in order and the first one that fires wins. If the zero trigger has priority and a zero breach occurs in May, the line is backward planned from May even when a safety stock breach happened earlier in March. The planning never reaches the later triggers once an earlier one fires.
How is the suggested quantity calculated?
The quantity comes from the triggers on ending inventory. For example, reorder point plus reorder quantity, calculated backwards from zero, with order modifiers applied. If you run the suggest-quantity-to-order action again, the values update.
Can I override the planned dates manually?
Yes. You can change the order date and supply date columns manually on any line if a specific item needs a different date than the template produced.
Does Direct Replenishment plan the same way as MRP?
No. With multiple inventory breaches, full MRP can handle them differently. Direct Replenishment uses the trigger order you define, so the result can differ. The trigger-based approach is the best Direct Replenishment can do with backward and forward planning.