Depending on the approach you have chosen, you will need a HANA or an ERP user. The tables which have to be authorized can be copied from the list below.
If you use the HANA connection you can create a hdbrole in your HANA database with the following statements to have all the rights you need.
If you want to make it easier you can simply authorize the schema of your ERP system with select rights.
role <your package name>::<your role name>{
--Standard Edition
catalog sql object "SAPHANADB"."DD26S": SELECT;
catalog sql object "SAPHANADB"."DD02L": SELECT;
catalog sql object "SAPHANADB"."DDLDEPENDENCY": SELECT;
--Premium Edition
catalog sql object "SAPHANADB"."DD27S": SELECT;
catalog sql object "SAPHANADB"."DD03T": SELECT;
--Extended Edition
}