I wanted to know the integration state of ERP system (like SAP) and Ethereum.
Is there an API that allow a smart contract to fetch information from a ERP to store that data?
Thanks in advance
Not specifically. However you could write your own server side daemon program which would basically act as an oracle:
As far as building the server side daemon is concerned there are several options for step (3):
You should probably pick one for which a good SAP connector library exists. Personally I would try python with sapnwrfc
Other thing to note is that storing large amounts of data on the blockchain is expensive so consider uploading data to SWARM or IPFS and storing the hash of the data in the contract.
sap is a complex database, but these guys at finlync have managed direct integration for sap to ethereum. suggest you reach out to them...