In a container assembly for a laser diode module in which a temperature control device is not incorporated in advance, a heat-insulative casing is adapted to accommodate the laser diode module. In general, the multi-phase DC-DC converter includes a multi-phase converter control system and a multi-phase power train. In both embodiments, the first polarization vector in the p-layer and second polarization vector in the n-layer create discontinuity at the interface resulting in a negative charge appearing at the interface. The interior portion has a vertical free edge positionable in contact with the side wall of a can. For each variable length field in a Structured Query Language statement such as CREATE table or ALTER table, the DBMS finds a matching historical record, determines an estimated optimal fixed portion length based on the matching historical record, and sets a space allocation length for the fixed length part of the variable length field based on the estimated optimal fixed portion length.