Working on Odata first time , Needs to know
Is it possible to map external object from Odata to standard object?
Is it needs to be done using custom field (using formula) in standard object.
You can change the field type for a custom field on an external object to a Lookup or Indirect Lookup to associate its values with a Standard object. Use a Lookup if the column in the external data holds Salesforce record ids, and an Indirect Lookup if it is a business key. Indirect lookups can only point to unique custom fields that are flagged as external identifiers.
Standard and custom objects can use External Lookups to create associations with External Objects.
External objects are really quite limited. It may be worth checking that link which is to official documents but it states that:
Formulas and roll-up summary fields can’t reference fields on external objects.
The only type of relationship you can have on there are lookup and external lookup, and indirect lookup relationships.
But as far as mapping is concerned I don't believe there is a way to do this with external objects.