Oracle表的主键

Question

I am trying to retrieve the primary keys for a table name EMPLOYEE as follows

    SELECT  cols.column_name
    FROM all_constraints cons, all_cons_columns cols
    WHERE cols.table_name ='EMPLOYEE'
    AND cons.constraint_type = 'P'
    AND cons.constraint_name = cols.constraint_name
    AND cons.owner = cols.owner
    ORDER BY cols.table_name, cols.position

The table EMPLOYEE exists for another user which also has a primary key called ID

So the result of the above query gives (ID, ID) instead of (ID) from the current user. How do I get only the primary keys of the tables belonging to the user's schema

Answer 1

1. Switch to USER_* views instead of ALL_* .
2. Eliminate conditions on the OWNER columns in your query.

---

• ALL_* views return everything the querying schema has access to including the objects the schema owns, in contrast to
• USER_* views returning only the objects the schema is owner of
• DBA_* views return all objects in database

Therefore, you can query USER_* views or you can query DBA_* views specifying the condition on the OWNER column.

In your case your query could look like this.

select
  cons.table_name
, cons.constraint_name
, cols.column_name
, cols.position
from user_constraints cons, user_cons_columns cols
where cons.constraint_name = cols.constraint_name
and constraint_type = 'P'
order by cons.table_name;

For more details about data dictionary and views' and their scope, consult the Data Dictionary and Dynamic Performance Views section in Concepts.