1. A database is made up of one or more tablespaces.
2. A tablespace is made up of one or more data files. These files might be cooked files in
a file system, raw partitions, ASM managed database files, or a file on a clustered file
system. A tablespace contains segments.
3. A segment (TABLE, INDEX, and so on) is made up of one or more extents. A segment
exists in a tablespace, but may have data in many data files within that tablespace.
4. An extent is a logically contiguous set of blocks on disk. An extent is in a single tablespace
and, furthermore, is always in a single file within that tablespace.
5. A block is the smallest unit of allocation in the database. A block is the smallest unit of
I/O used by a database.
1. 一个数据库是由一个 或者多个表空间组成;
2. 一个表空间是由一个或者多个数据文件组成，这些文件可能在一个文件系统，裸设备，ASM管理的数据库文件，或者在一个集群文件系统中，一个表空间是由多个段组成
3. 一个段（表，索引，等等）是由一个或多个区组成，一个段只能存在于一个表空间中，不能夸表空间
4.区是由连续的逻辑磁盘块组成
5. 块是数据库中最小的分配单元