Schema
Schema is a collection of database objects. Schema contains various objects such as tables, views, sequences, stored procedures, synonyms, indexes, clusters, database links.
The relationship between user and Schema
A user corresponds to a default schema, and the Schema name is the same as the user name.
When operating an object, if Schema is not specified, the default Schema of the current user is used. For example, if the current user is scott, you can directly access it by select * from emp.
Tablespace
Oracle tablespace is a logical concept. It does not exist physically. The data files that really store data are data files. A database has multiple tablespaces, and a tablespace contains multiple data files. Tablespace is the smallest unit for Oracle database recovery, and it houses many database entities, such as tables, views, indexes, clusters, fallback segments and temporary segments.
When creating a tablespace, a data file is created on the physical disk as the physical storage space for database objects (users, tables, stored procedures, etc.). When the data file space is insufficient, the data file can be expanded or added.
Comes with table space
Oracle comes with its own tablespace as follows:
- SYSAUX
- SYSTEM
- TEMP
- UNDO
- USERS
The relationship between user and tablespace
You can specify a tablespace for a user when creating it, and if the default tablespace is not explicitly specified, the users tablespace is specified.
A user generally only uses one tablespace (the default tablespace), but can also specify other tablespaces when creating a table.