1) The most important difference, the importance of data stored in different sys】 【all oracle data dictionary base tables and views are stored in the sys user, these base tables and views for the oracle operation is essential, by the maintenance of the database itself, any user can manually change. sys user has dba, sysdba, sysoper other role or authority, is the highest authority of the user oracle.
【】 User system for internal data storage sub-level, such as the oracle of some features or tools of management information. system users have the role of general dba privileges.
2) Second, the difference between the different permissions.
【】 Users can only use the normal system as landing em, unless you give it a sysdba of system privileges or syspoer system privileges.
Sys】 【user has "SYSDBA" or "SYSOPER" system permissions, landing em can only use these two identities, which can not normal.
To sys user login Oracle, the implementation of select * from V_ $ PWFILE_USERS; can be found to have a sysdba privileged user, such as:
SQL> select * from V_ $ PWFILE_USERS;
USERNAME SYSDBA SYSOPER
SYS TRUE TRUE
Sysdba and sysoper difference between the two system privileges
normal, sysdba, sysoper What is the difference
normal is a normal user the other two, you have their permission to examine the known
sysdba has the highest system privileges, after landing a sys
sysoper mainly used to start, shut down the database, sysoper after the user is a public landing
sysdba and sysoper are system privilege, also known as administrative privilege, have such a database open and close like a number of administrative level permissions sysdba and sysoper specific permission may have a look below:
system if the normal login, it is actually a common dba user, but if as sysdba login, the result in fact it is the user logged on as sys This is similar to Linux's sudo feeling inside, from the login information which we can see out. Therefore, after connecting to the database as sysdba, create the objects are actually generated in the sys. The same is true of other users, if as sysdba login as sys user is logged on to see the following experiment:
SQL> create user strong identified by strong;
The user has been created.
SQL> conn [email = strong / strong @ magick] strong / strong @ magick [/ email] as sysdba;
SQL> show user;
USER is "SYS"
SQL> create table test (a int);
Table has been created.
SQL> select owner from dba_tables where table_name = 'test';
Not the selected row / / create the table because oracle automatically converted to uppercase, so use lower case when the investigation does not exist;
SQL> select owner from dba_tables where table_name = 'TEST';
Ø dba and sysdba difference
dba, sysdba What is the role of the two systems in the illustrate this difference between what I need to say a few words before the creation of oracle service instance → · start to create an instance of → · create the database (system table space is required)
Start the process of loading the database instance starts → · → · open database
sysdba, oracle instance is managed, its existence does not depend on the entire database is fully started, as long as the instance starts, and he is there, in order to login as sysdba, loading the database, open the database. Only the database open, or fully activated the entire database, dba role in the existence of only the basis of!