A comma-delimited list of schemas to import. This parameter is relevant only to users with the IMP_FULL_DATABASE role. The parameter enables you to import a subset of schemas from an export file containing multiple schemas (for example, a full export dump file or a multischema, user-mode export dump file).
Schema names that appear inside function-based indexes, functions, procedures, triggers, type bodies, views, and so on, are not affected by FROMUSER or TOUSER processing. Only the name of the object is affected. After the import has completed, items in any TOUSER schema should be manually checked for references to old (FROMUSER) schemas, and corrected if necessary.
You will typically use FROMUSER in conjunction with the Import parameter TOUSER, which you use to specify a list of usernames whose schemas will be targets for import (see "TOUSER"). The user that you specify with TOUSER must exist in the target database before the import operation; otherwise an error is returned.
If you do not specify TOUSER, then Import will do the following:
Import objects into the FROMUSER schema if the export file is a full dump or a multischema, user-mode export dump file
Create objects in the importer's schema (regardless of the presence of or absence of the FROMUSER schema on import) if the export file is a single-schema, user-mode export dump file created by an unprivileged user