Example from item_db.sql
REPLACE INTO `item_db` VALUES (1231,'Bazerald','Bazerald',4,20,NULL,500,70,NULL,1,NULL,0x028F5EEE,7,2,2,4,36,1,1,'bonus bAtkEle,Ele_Fire; bonus bInt,5; bonus bMatkRate,10;',NULL,NULL);
Example from item_db_re.sql
REPLACE INTO `item_db_re` VALUES (1231,'Bazerald','Bazerald',4,20,NULL,500,'70:105',NULL,1,NULL,0x028F5EEE,7,2,2,4,'36',1,1,'bonus bAtkEle,Ele_Fire; bonus bInt,5;',NULL,NULL);
Of course you have to replace the values with your desired values and the table name with item_db2 or item_db2_re.
Field explanation can be found here: http://rathena.org/wiki/Custom_Items