The most important properties of a component are the ones that permit to define it unequivocally. This should be accomplished with the minimum information for clarity and simplicity. In your Bill Of Material you want to have the minimum number of columns that display information to identify a component.

These column values are not unique between them but their combination are like in a relational database where a key (a single column or a set of columns) uniquely identifies each row of a table.

External Components

In this case, we cannot use the Manufacturer Reference (or Part Number) as key because there is nothing that guaranties that another Manufacturer does not use the exact same number for a completely different component. See the article about the Definition of the Word Component.

The odds seems low that in the same BOM two different components can have the same Part Number, but it is not that uncommon. I have seen it in several occasions

To not take any chances, the Manufacturer should be considered along the Part Number to create something more unique.

• Part Number
• Manufacturer

Be careful to use the actual Manufacturer and not the Distributor because a component is manufactured by one company but can be distributed by several. The Distributor might be using its own Part Number in place of the Manufacturer‘s one which could create confusing for sourcing the component.

Moreover, specifying a Distributor in place of a Manufacturer might implicitly force the person in charge of the purchasing to use that Distributor instead of looking for alternatives with better pricing…

Using the Distributor‘s name would also lead to a difficult choice of where to save the component’s model file. See the article about the Folders Structure.
If you are using miniPDM, you can use the Component Extended Properties to store the Distributor Name and the Distributor Reference so there is no reason not to use the Manufacturer as base. See the article about the Price Conditions.

If you don’t know the Manufacturer name as it is not always disclosed by the Distributor(s) then go for the Distributor Name of the one you use the most. If later you discover the name of the Manufacturer (on the component package when you receive it?) you can always change it and very easily if you have followed the Files Naming advice.

Internal Components

If the component is not External but Internal the Manufacturer is you. You can just use your company name.
The Part Number is in that case your own creation whether you used the
Unique Identifier Generator of miniPDM or a system on your own. In most cases it will be the same as the Document Number if you have chosen to follow the advice given in the article about the Component Unique Identifier.