The difference between ALTER DATABASE and ALTER SYSTEM and ALTER session

1, the system is the instance level, database is the data base level, session is conversation level.

2, about these three levels of changes in the following general

Database-level (relatively large) > instance-level > Session-level (for current conversations only)

3. Related attributes

"Alter session SET *****=****"//valid for current session

"Alter system set *****=****"//Is permanent (System) valid

"ALTER DATABASE Set *****=****"//is usually changed to static parameters

ALTER DATABASE changes the properties of a data base, generally changing the physical, can be seen

For example: Alter dtabase rename DataFile

Alter system dynamically alters the properties of a database routine, which is generally logical, invisible

For example: Alter system set Db_cache_size

Alter session changes the properties of a session

For example: Alter session set Nls_language

This article is from the "Travel Life" blog, please be sure to keep this source http://felixgzf.blog.51cto.com/4108324/1792157

The difference between ALTER DATABASE and ALTER SYSTEM and ALTER session