Schema objects are logical data storage structures. Schema objects do not have a one-to-one correspondence to physical files on disk that store their information. However, Oracle stores a schema object logically within a tablespace of the database. The data of each object is physically contained in one or more of the tablespace's datafiles. For some objects such as tables, indexes, and clusters, you can specify how much disk space Oracle allocates for the object within the tablespace's datafiles. Figure 5 - 1 illustrates the relationship among objects, tablespaces, and datafiles.
Figure 5 - 1. Schema Objects, Tablespaces, and Datafiles
There is no relationship between schemas and tablespaces: a tablespace can contain objects from different schemas, and the objects for a schema can be contained in different tablespaces.