How to see constraints in oracle database

red@red_dev> desc all_constraints;                                                                                                                           

Name              Null?    Type       
----------------- -------- ------------
OWNER             NOT NULL VARCHAR2(30)
CONSTRAINT_NAME   NOT NULL VARCHAR2(30)
CONSTRAINT_TYPE   NULL     VARCHAR2(1)
TABLE_NAME        NOT NULL VARCHAR2(30)
SEARCH_CONDITION  NULL     LONG       
R_OWNER           NULL     VARCHAR2(30)
R_CONSTRAINT_NAME NULL     VARCHAR2(30)
DELETE_RULE       NULL     VARCHAR2(9)
STATUS            NULL     VARCHAR2(8)
DEFERRABLE        NULL     VARCHAR2(14)
DEFERRED          NULL     VARCHAR2(9)
VALIDATED         NULL     VARCHAR2(13)
GENERATED         NULL     VARCHAR2(14)
BAD               NULL     VARCHAR2(3)
RELY              NULL     VARCHAR2(4)
LAST_CHANGE       NULL     DATE       
INDEX_OWNER       NULL     VARCHAR2(30)
INDEX_NAME        NULL     VARCHAR2(30)
INVALID           NULL     VARCHAR2(7)
VIEW_RELATED      NULL     VARCHAR2(14)