Can anyone please help on this?I dont know why i am getting SQL Error: ORA-00001: unique constraint (RO_MARGE_TABLE_PK) violated : insert into RO_MARGE_TABLE ( PROMOTION_OFFER_ID, PROMOTION_CODE, SYS_CREATION_DATE, SYS_UPDATE_DATE, OPERATOR_ID, APPLICATION_ID, DL_SERVICE_CODE, DL_UPDATE_STAMP, SPEED, PREMIUM_TIERS, PACKAGE_TYPE, EFFECTIVE_DATE, EXPIRATION_DATE, PROMOTION_AMOUNT) 
select PROMOTION_OFFER_ID, DECODE(PROMOTION_CODE,NULL,NULL,NVL(RTRIM(PROMOTION_CODE),' ')), SYS_CREATION_DATE, SYS_UPDATE_DATE, OPERATOR_ID, DECODE(APPLICATION_ID,NULL,NULL,NVL(RTRIM(APPLICATION_ID),' ')), DECODE(DL_SERVICE_CODE,NULL,NULL,NVL(RTRIM(DL_SERVICE_CODE),' ')), DL_UPDATE_STAMP, DECODE(SPEED,NULL,NULL,NVL(RTRIM(SPEED),' ')), DECODE(PREMIUM_TIERS,NULL,NULL,NVL(RTRIM(PREMIUM_TIERS),' ')), DECODE(PACKAGE_TYPE,NULL,NULL,NVL(RTRIM(PACKAGE_TYPE),' ')), EFFECTIVE_DATE, EXPIRATION_DATE, PROMOTION_AMOUNT FROM SCHEMT098.MARGE_TABLE@DBLINK865;