I would like to know if there are any resources where they clearly explain how a database is used in an ERP application such as SAP.

Or else give me some keywords to search on google for this information.

I searched a lot but did not get the desired information.I have good knowledge of DB concepts.

For EX: when inventory is updated through the interface , X table Y column stores the new value.... and if we want to have Z information we have to query using so and so

Try a search for "open source enterprise resource planning". Whatever you need ought to be in either the documentation or, if all else fails, the underlying source code.

Open Source solutions are probably the only place where you'll find this information fully disclosed. Proprietary software vendors usually don't reveal much about the database because A) they reserve the right to change the internals at any time B) their preferred / officially supported method for customers to access the data is through the application interfaces provided and not directly from the database.

There is a third party solution that exposes some of the metadata from the SAP database model. I've not used this myself however.
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