There is a graph that clearly shows the difference between the physical and logical structure of Oracle, as explained by:
Each database must consist of one or more table spaces. (One-to-many relationship)
Each tablespace must consist of one or more data files
file). (One-to-many relationship)
Each table space can contain one or more segments. (One-to-many relationship)
Each data file must consist of one or more operating system blocks (OS bolck). (One-to-many relationship)
Each segment must consist of one or more intervals (a-to-many relationship)
Each interval must consist of one or more Oracle data blocks (Oracle
Block). (One-to-many relationship)
Each interval must be positioned and located within a data file, and the space in the data file can be assigned one or more intervals (many-to-one relationship)
Each Oracle data block must consist of one or more operating system data blocks (two-to-many relationships) physical structure
1. Data file
is the operating system file that holds Oracle data. The database creation phase creates many data files that can hold data dictionaries, Sysaux tablespace data, and other tablespace data that you want to create at the same time.
2. The operating system database (OS
block) is the smallest allocation unit used by the file system. For example: 4KB or 8KB
logical Structure
1. The Tablespace (tablespace) system table space contains a data dictionary (a table that describes the structure of the database itself, all objects, users, and roles). The system table space is where the data dictionary is located in the database. If there is no system table space, the database will not work
after creating the database, you need to create additional tablespaces that store the data. The
2. Segment (segment) table space is assigned to a number of segments. A segment is a stored object, such as a table or an index. Note: Views do not store data, so not segment
3. A zone (extent) is a collection of several contiguous blocks of data allocated for a segment. You can have a local administrative area within a tablespace
4. A block is the smallest unit of I/O in the database. When a database needs to read data, it always cannot read only one record, but must read the entire block of data. You cannot modify the block capacity
If you specify the block capacity when you create the tablespace.
