Get information on all the column constraints you have access to using all_cons_columns. : all_cons_columns « System Tables Data Dictionary « Oracle PL/SQL Tutorial

1. Oracle PL/SQL Tutorial
2. System Tables Data Dictionary
3. all_cons_columns

SQL>
SQL> desc all_cons_columns;
 Name              Null?    Type
 ------------------

 OWNER             NOT NULL VARCHAR2(30)
 CONSTRAINT_NAME   NOT NULL VARCHAR2(30)
 TABLE_NAME        NOT NULL VARCHAR2(30)
 COLUMN_NAME                VARCHAR2(4000)
 POSITION                   NUMBER

SQL>
SQL> --select * from all_cons_columns;
SQL>