Database Structure and Space Management
Logical Database Structure
* Schema/Schema object(the logical structures that directly refer to the DB’s data
a schema is owned by a user who has the same name as the schema)
* Data block
Online(accessible)and Offine(not accessible)
* Databse, TableSpaces, and Datafiles
Physical Database Structures
* Datafiles (the charateristics of datafiles)
- A datafile can be associated with only one database.
- Could extend automatically
- One or more datafiles fomr a tablespace
- To reduce the amount of disk access, data is pooled in memory and written to the
appropriate datafiels all at one, as determined by the databse writer process background process.
* Redo log files (Every Oracle database has a set of two or more redo log files)
- A redo log is made up of redo entries(redo records)
- Maintain the redo log files on different disks using multiplexed redo log
- Rolling forward, the process of applying the redo log during a recovery operation
* Control Files
- Every Database has a control file.