create table T (
    ID          integer NOT NULL,
    REF_ID      integer,
    NAME        varchar(100),

select ID
  from T
 group by ID
having count(*) > 1

select *
  from T
 where ID = 123

ALTER TABLE T ADD CONSTRAINT PK_T PRIMARY KEY (ID);

update T set ID = ID

Summary of validation errors
        Number of index page errors     : 1

Summary of validation errors 
	Number of index page errors	: 2

alter index MY_INDEX active

Summary of validation errors 
	Number of index page errors	: 1

select ID, count(*)
  from T
 group by ID
having count(*) > 1

select *
  from T
 where ID = 123

SQL> alter index PK_T active;
SQL> commit;
SQL>

select *
  from T
 where ID = 123

Summary of validation errors 
	Number of index page errors	: 1

PC-12	Fri Mar 18 18:52:53 2016
	Database: err_db
	Index 16 is corrupt (record 0 have missing entries) in table T (192)

CREATE TABLE T (
    ID                  INTEGER NOT NULL,
    REF_ID              INTEGER,
    NAME1               VARCHAR(1000),
    NAME2               VARCHAR(60),
    COMMENTS            VARCHAR(255),
    DELETED             SMALLINT DEFAULT 0 NOT NULL,
    CREATEDATE          DATE,
    CREATOR             VARCHAR(31),
    GUID                CHAR(36) NOT NULL
);

ALTER TABLE T ADD CONSTRAINT PK_T PRIMARY KEY (ID);
ALTER TABLE T ADD CONSTRAINT UNQ_T UNIQUE (REF_ID);