★ B+tree index {vfid: (7538, 2) 에러 확인 부탁드립니다.

1번째 질의 실행이 실패하였습니다.
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DELETE FROM ORDER_MST WHERE SUBSTRING(ORDER_DATE,0,6) >= '201310';

실행 오류 : -407
Unknown key '12013102800011M' referenced in B+tree index {vfid: (7538, 2), rt_pgid: 8070, key_type: character varying}.[CAS INFO - localhost:30000,1,4512],[SESSION--18176],[URL-jdbc:cubrid:localhost:30000:dek_report:dba:********:].

CREATE TABLE order_mst(
order_num character varying(20) NOT NULL,
custom_code character varying(8) NOT NULL,
order_date character varying(8) NOT NULL,
export_yn character varying(1) NOT NULL,
order_type character varying(2) NOT NULL,
money_unit character varying(3) NOT NULL,
order_o numeric(18,4) DEFAULT 0.0000,
exchg_rate_o numeric(8,4),
remark character varying(40),
bill_type character varying(2),
create_flag character varying(1) DEFAULT 'S',
change_ser_no integer DEFAULT 0
) COLLATE euckr_bin ;
CREATE INDEX order_mst_idx00 ON order_mst(order_num);