【導(dǎo)讀】系統(tǒng)需要實(shí)現(xiàn)的設(shè)計(jì)方法作了介紹。該系統(tǒng)的基本功能主要包括用戶購(gòu)買(mǎi)和。用戶購(gòu)買(mǎi)系統(tǒng)包括商品查詢，訂單查詢和商品訂購(gòu)；管理員系。這個(gè)系統(tǒng)被劃分成兩塊：即后臺(tái)數(shù)據(jù)庫(kù)和Web站點(diǎn)。結(jié)構(gòu)化設(shè)計(jì)的，所以它能非常便利地?cái)U(kuò)展成適合于未來(lái)更加復(fù)雜的環(huán)境。之，該系統(tǒng)是一個(gè)可靠而有用的系統(tǒng)。

　　

【正文】 d him opened. Hurriedlyreclosing the panel cover, the old man slipped deeper into the shadows. Adetachment of troopers had appeared in the portal, and the officer in charge moved towithin a couple of meters of the motionless, hidden figure. Secure this area until the alert has been cancelled. As they began to disperse, Kenobi became one with the dark. Chewbacca grunted and wheezed, and barely succeeded in forcing his thic k torsothrough the hatchway opening with Luke39。s and Solo39。s help. That acplished,L uke turned to ta ke stoc k of their surroundings. The hallway they had emerged into showed dust on the f loor. It gave theimpression of not having been used since the station had been built. Probably it wasonly a repair access corridor. He had no idea where they were. Something hit the wall behind them with a massive thunk, and Luke yelled foreveryone to watch out as a long, gelatinous limb wor ked its way through the hatchand flailed hopefully about in the open corridor. Solo aimed his pistol at it as Leiatried to slip past the halfparalyzed Chewbacca. Somebody get this big hairy walking carpet out of my way. Suddenly shenoticed what Solo was preparing to do. No, wait! It39。 ll be heard! Solo ignored her and fired at the hatchway. The burst of energy was rewardedwith a distant roar as an avalanche of weakened wall and beaming all but buried thecreature in the chamber beyond. Magnified by the narrow corridor, the sounds continued to roll and echo for longminutes afterward. Luke shook his head in disgust, realizing that someone like Solowho spoke with the mouth of a gun might not always act sensibly. Until now he hadsort of looked up to the Corellian. But the senseless gesture of firing at the hatchwaybrought them, for the first time in Luke39。s m ind, to the same level. The Princess39。s actions were more surprising than Solo39。s however. Listen, shebegan, staring up at him, I don39。t know where y ou came from, but I39。m grateful.Almost as an afterthought she glanced back at Luke, adding, To both of y ou. Herattention turned back to Solo. But from now on you do as I tell you. Solo gaped at her. This time the smug smile wouldn39。t e. Look, YourHoliness, he was finally able to stammer, let39。s get something straight. I takeorders only from one personme. It39。s a wonder you39。re still alive, she shot back smoothly. A quick look downthe corridor and she had started determinedly of f in the other direction. Solo looked at Luke, started to say something, then hesitated and simply shookhis head slowly. No reward is worth this. I don39。t know if there39。s enough credit inthe universe to pay for putting up with her? Hey, slow down! Leia had started around a bend in the corridor, and they ran swiftly to catch upwith her. The half dozen troops milling around the entrance to the power trench were moreinterested in discussing the peculiar disturbance in the detention block than in payingattention to their present boring duty. So engrossed were they in speculation as tothe cause of the trouble that they failed to notice the fey wraith behind them. Itmoved from shadow to shadow like a nightstalking ferret, freezing when one of thetroopers seemed to turn slightly in its direction, moving on again as if walking on air. Several minutes later one of the troopers frowned inside his armor, turning towhere he thought he had sensed a movement near the opening to the main w as nothing but an undefinable something, which the ghost like Kenobi hadleft behind. Acutely unfortable yet understandably unwilling to confess tohallucinations, the trooper turned bac k to the more prosaic conversation of his fellows. Someone finally discovered the two unconscious guards tied in the service lockerson board the captured freighter. Both men remained atose despite all efforts torevive them. Under the direction of several bic kering officers, troopers carried their twoarmorless rades down the ramp and toward the nearest hospital bay. On the waythey passed two forms hidden by a small opened service panel. Threepio and Artoowent unnoticed, despite their proximity to the hangar. As soon as the troops had passed, Artoo finished removing a soc ket cover andhurriedly shoved his sensor arm into the opening. Lights menced a wild flashingon his face and smoke started issuing from several seams in the small 39。droid before afrantic Threepio could pull the arm free. Immediately the smoke vanished, the undisciplined blinking faded to emitted a few wilted beeps, successfully g iving the impression of a human whohad expected a glass of mild wine and instead unwittingly downed several gulps ofsomething 180 proof. Well, next time watch where you stick your sensors, Threepio chastised hispanion. You could have fried your insides. H e eyed the socket. T hat39。s apower outlet, stupid, not an information terminal. Artoo whistled a mournful apology. Together they hunted for the proper outlet. Luke, Solo, Chewbacca and the Princess reached the end of an empty deadended before a large window, which overlooked a hangar, giving them asweeping, tantalizing view of the freighter just below. Pulling out his link and looking around them with increasing nervousness,Luke spoke into the pickup. See Threepio? do you copy? There was a threatening pause, then, I read you, sir. We had to abandon theregion around the office. Are you both safe? For the moment, though I39。m not sanguine about my old age. We39。re in themain hangar, across from the ship. Luke looked toward the bay window in surprise. I can39。t see you across thebay we must be right above you. Stand by. We39。ll join you as soon as we can.He clic ked off, smiling suddenly at Threepio39。s reference to his old age.Sometimes the tall 39。droid was more human than people. Wonder if the old man was able to knock out the tractors. Solo w