Shulou(Shulou.com)06/01 Report--

Introduction of data dictionary and dynamic performance view

1. Data dictionary of database

(1) the data dictionary of certain objects owned by DBA_.

Only the system user has the right to query

(2) objects created by current users of ALL_ + objects granted to current users by other users

Current user

(3) objects created by the current user of USER_

Current user

Operation example:

Unlock a user hr and change the password

SQL > alter user hr account unlock

User altered.

SQL > alter user hr identified by hr

User altered.

Under scott user, view the table under hr user

SQL > conn scott/scott

Connected.

SQL > select * from hr.jobs

Select * from hr.jobs

*

ERROR at line 1:

ORA-00942: table or view does not exist-error is reported, table or view does not exist

SQL > conn hr/hr

Connected.

SQL > grant select on jobs to scott;-Grant select permission

Grant succeeded.

SQL > insert into hr.jobs values ('HR_REP','asdfasd',1232,5545)

Insert into hr.jobs values ('HR_REP','asdfasd',1232,5545)

*

ERROR at line 1:

ORA-01031: insufficient privileges

Under a user: the following statements are equivalent:

Select * from user_objects where object_type='TABLE'

= select * from user_tables

two。 Dynamic performance View

Select * from v$session

Select * from v$process

Exercise: query DBA_OBJECTS under SYS, but cannot be found under scott, authorize the query to scott, so that scott can query this data dictionary

SQL > conn scott/scott

Connected.

SQL > select * from dba_objects

Select * from dba_objects

*

ERROR at line 1:

ORA-00942: table or view does not exist

SQL > conn / as sysdba

Connected.

SQL > grant select on dba_objects to scott

Grant succeeded.

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