Imagine if I have an account with contract. Is it allowed for me to look up tables of some another contract from my contract action?
Include the definition of multi_index of the other contract in your source code, and instantiate multi_index with
code is the account name of the other contract you want to read. (You may pass
_self usually, because you read and write the multi-index table of your contract.)
The multi-index table of other contracts is read-only. You cannot change its value from your contract.