A schema is a collection of database objects. It is owned by a database user and has the same name as that user. Schema objects are the logical structures that directly relate to the data in the database. There is NO relation between tablespace and schema.
Schema Objects:
- Tables
- contains rows and colums (just like mysql). - Indexes
- just like mysql indexes — speeds up searches. - Views
- can be thought of as stored query. You can do most operations (select, insert..) on a view. If the view is ‘updateable’ then the operations affect the actual data used to create the view. - Clusters
- groups of one or more tables that are stored together because they share common columns. - Synonyms
- a user-defined name or any ‘nameable’ object in the database. Do not actually take up storage except in the ‘data dictionary’.
