A schema is a collection of database objects that are owned by a particular user. For a production database, this user typically represents not a person but an application. A schema has the same name as the user that owns the schema. Schema objects are the logical structures that directly refer to a database’s data. Schema objects include structures such as tables, views, and indexes.
You can create and manipulate schema objects by using SQL or Enterprise Manager. When you use Enterprise Manager, the underlying SQL is generated for you.
Note: A schema does not necessarily need to be directly related to a single tablespace. You can define configurations so that objects in a single schema can be in different tablespaces and so that a tablespace can hold objects from different schemas.
When you create the database, several schemas are created for you, including the following two important schemas:
- SYS schema: Contains the data dictionary
- SYSTEM schema: Contains additional tables and views that store administrative information
