ALTER SESSION SET CURRENT_SCHEMA

You can use below command to avoid the use of public synonyms.  By setting the current_schema attribute to the schema owner name it is not necessary to create public synonyms for production table names

ALTER SESSION SET CURRENT_SCHEMA = "XX_SCHEMA_NAME"

Ex:  ALTER SESSION SET CURRENT_SCHEMA = "APPS"

Queries to Check Oracle Application and Database Versions

Application Version:

SELECT RELEASE_NAME, APPLICATIONS_SYSTEM_NAME, ARU_RELEASE_NAME FROM apps.fnd_product_groups

Database Version:

 SELECT * FROM v$version