Embedding internal product code or manufacturer information into a schematic

[Pack34]

The end goal is to ensure global accuracy of a BOM with minimal effort.

Two schools of thought for this would be to attribute an internal part number to the component and then pull the manufacturer information, second sourcing, etc from an external spreadsheet or database. Or to embed all of the manufacturer information directly into that part. 

I'm quite fond of the second approach. Anything to make it so that when you export the BOM from the schematic, it should be the final with no alterations. I feel it cuts out a step and then when you inspect a part in a schematic you'll know exactly what the primary and secondary part numbers are without referencing an external database.

What's the general consensus here?

All new designs I'm working with are in Altium with legacy stuff in Eagle. With Altium I can link a part from a distributor directly to a schematic and in Eagle I tend to dump all the component information into a spreadsheet and have some formulas generate all of the XML information behind the component libraries to semi-automate library building.

[floobydust]

The in-house part numbering scheme allows Engineering to see what is already commonly used,  Purchasing can get the best pricing for higher volumes - but it's another parts system to maintain. Vendor qualification, parts qualification, and designs can end up with the same or similar parts from different manufacturers which can cause surprises.

If you're using in-house part numbers, stick to that in the schematics.
Never put mfgr specifics in the schematics then, as you are bastardizing your in-house part numbering system.

You will always have multiple vendors that can supply a part, some with subtle differences. Someone, usually engineering, decides what parts are suitably qualified for the in-house number. Exceptions or special parts should have a unique in-house part number, not a note on the schematic to use X part for X manufacturer.

Otherwise, only use manufacturer's part numbers in your schematics.
It depends on your companies size and if the designs are really sensitive to a component's specifics.

[Pack34]

I don't currently use an in-house part numbering scheme.

I started to implement one at a previous job but I abandoned it due to it feeling like it was an added step and another database to maintain.

So far I've been including the following fields on all components with the information preceding by "1_" is the primary source and "2_" being the secondary.

1_DESC
1_DIST
1_DIST_PN
1_MFG
1_MFG_PN
2_DESC
2_DIST
2_DIST_PN
2_MFG
2_MFG_PN

[floobydust]

Four part numbers in your SCH to maintain, and that can be a big hassle.

I just put the root part number in and use my brain to translate to a finished BOM or decide a vendor.

Because the part number can also contain the reel size. Would you spec the 3,000 or 10,000 part reel, for a single part?
A simple diode like BAV99 NXP has BAV99,215 or BAV99,235 I still haven't figured out the difference.

Ideally you generate a magic BOM from your schematic, but very difficult to accommodate prototype builds vs full production and then do Purchasing's job with "how many do I order, should I get a reel?"