Each table in a database has a unique name.
If you specify a table name in an SQL statement without specifying an owner or a schema, then the database system searches through the database catalog for the table name in the following order:
Catalog part of the current owner
Set of PUBLIC synonyms
Catalog part of the database administrator who created the user currently logged on
Catalog part of the database system administrator
Catalog part of the owner of the system tables
You can only access tables from another owner or schema if you already have the necessary privileges.