A table space can only belong to a database
There is a minimum of a control file for each database (suggest 3, which is placed on different disks)
There is a minimum of a table space per database (System table space)
The purpose of establishing the SYSTEM table space is to try the same table as possible to improve the efficiency of use, and should only store data dictionary.
There are fewer online log groups for each database, each set of one online log file
A data file can only belong to a table space
Once a data file is added to a table space, it is no longer removed from this table space, and can no longer be added to other tablespaces.
Establish new tablespace needs to create new data files
Data files are formatted by Oracle to Oracle blocks, in previous versions of Oracle9i, the size of the Oracle block is set when the database is created,
And in the future, you can't change, you must change, you can only rebuild the database.
A segment segment can only belong to a table space, but can belong to multiple data files.
One area extent can only belong to a data file, that is, intervals, unable to cross the data file
PCTFREE and PCTUSED summation cannot be greater than or equal to 100
A single transaction cannot span multiple returns
Index table does not contain ROWID values
There is no benefit of returning to different sizes.
After commit, the data is not necessarily written immediately (data files)
An a transaction will be written to the redo log even if it is not submitted.
ORACLE 8.0.4, the default database established during initial installation, instance is named orcl
One block is 16KB (2K, 4K, 8K, 16K) Each database maximum file number (by block size) 2K block 2000 file 4K block 40000 file 8K block or above 65536 files
Oracle Server can start multiple databases at the same time
A plurality of version of the Oracle database system can be installed on a set of operating systems (UNIX can, NT can not be)
A set of Oracle database systems can have multiple Oracle databases and their corresponding instances
Each Oracle database has a database instance (except for OPS)
Therefore, a set of operating systems can have multiple Oracle database instances to start
