MD03 generates the requirement for a material for its own level, irrespecive of whether a BOM is attached or not.
But if I want to generate the requirement for all BOM items attached to a material then what should be done?
Use the transaction MD02 for this purpose. It helps use run a single item, multi level MRP for a material.
It starts with the planning of the material that you have entered on the selection screen , then, does a BOM explosion and generates the dependent requirements for the components.
You can use this transaction to view the results at each level and for every component. Once the results are saved, use the Determine New Breakpoint option and you can see where do the requirements / recceipts come for each component.
Hope this helps.