【導(dǎo)讀】建立和維護(hù)以及前端應(yīng)用程序的開發(fā)兩個(gè)方面。對于前者要求建立起數(shù)據(jù)一致性。和完整性強(qiáng)、數(shù)據(jù)安全性好的庫。而對于后者則要求應(yīng)用程序功能完備,易使用。息以用戶管理等六個(gè)方面。系統(tǒng)可以完成對各類信息的瀏覽、查詢、添加、刪除、系統(tǒng)的核心是添加、修改和刪除三者之間的聯(lián)系，每一個(gè)表的修改。此外，系統(tǒng)有完整的用戶添加、刪除和。密碼修改功能，并具備報(bào)表打印功能。題等方面，較為系統(tǒng)地介紹了“水表管理系統(tǒng)”課題開發(fā)的整個(gè)過程。的成本得到及時(shí)準(zhǔn)確的信息，做到較好的控制。現(xiàn)在的、預(yù)測未來的有關(guān)企業(yè)內(nèi)部及其環(huán)境的信息，以幫助他們進(jìn)行決策。今天，計(jì)算機(jī)的價(jià)格已經(jīng)十分低廉，性能卻有了長足的進(jìn)。大的提高人們的工作效率。使敏感文檔更加安全。計(jì)算機(jī)的應(yīng)用及普及到經(jīng)濟(jì)和社會(huì)生活的各個(gè)領(lǐng)域。這大大地阻礙了人類經(jīng)濟(jì)的發(fā)展。近年來，隨著城市家庭數(shù)量日益增多，家。數(shù)據(jù),這對于查找、更新和維護(hù)都帶來了不少的困難。這樣的機(jī)制已經(jīng)不

　　

【正文】 should know how agreeable and pleasant allthese things are。 and if all such occupations were managed onincorrupt principles, they would be honoured as we honour a motheror a nurse. But now that a man goes to de sert places and builds bouseswhich can only be reached be long journeys, for the sa ke of retailtrade, and receives strangers who are in need at the welerestingplace, and gives them peace and calm when they are tossed bythe storm, or cool shade in the heat。 and then instead of behavingto them as friends, and showing the duties of hospitality to hisguests, treats them as enemies and captives who are at his mercy,and will not release them until they have paid the most unjust,abominable, and extortionate ransomthese are the sort of practices,and foul evils they are, which cast a reproach upon the succour ofadversity. And the legislator ought always to be devising a remedy forevils of this nature. T here is an ancient saying, which is also a trueoneTo fight against two opponents is a difficult thing, as isseen in diseases and in many other cases. And in this case also t hewar is against two enemieswealth and poverty。 one of whom corruptsthe soul of man with luxury, while the other drives him by pain intoutter shamelessne ss. What remedy can a city of sense find against thisdisease? In the first place, they must have as few retail traders aspossible。 and in the second place, they must assign the occupationto that class of men whose corruption w ill be the least injury tothe state。 and in the third place, they must devise some way wherebythe followers of these occupations themselves will not readily fallinto habits of unbridled shamelessness and meanness. After this preface let our law run as follows, and may fortunefavour us:No landowner among the Mages, w hose city the God isrestoring and resettlingno one, that is, of the 5040 families,shall bee a retail trader either voluntarily or involuntarily。neither shall he be a merchant, or do any service for privatepersons unless they equally serve him, except for his father or hismother, and their fathers and mothers。 and in general for his elderswho are freemen, and whom he serves as a freeman. Now it isdifficult to determine accurately the things w hich are worthy orunworthy of a freeman, but let those who have obtained the prize ofvirtue give judgment about them in accordance with their feelings ofright and wrong. He who in any way shares in the illiberality ofretail trades may be indicted for dishonouring his race by any one wholikes, before those who have been judged to be the first in virtue。and if he appear to throw dirt upon his father39。s house by anunworthy occupation, let him be imprisoned for a year and abstain fromthat sort of thing。 and if he repeat the offence, for two years。 andevery time that he is convicted let the lengt h of his imprisonmentbe doubled. This shall be the second law:He who engages in retailtrade must be either a metic or a stranger. And a third law shallbe:In order that the retail trader who dwells in our city may be asgood or as little bad as possible, the guardians of the law shallremember that they are not only guardians of those who may be easilywatched and prevented from being lawless or bad, because they arewellborn and bred。 bu t still more should they have a watch overthose who are of another sort, and follow pursuits w hich have a verystrong tendency to m ake men bad. And, therefore, in respect of themultifarious occupations of retail trade, that is to say, in respectof such of them as are allowed to remain, because they seem to bequite necessary in a stateabout these the guardians of the law shouldmeet and ta ke counsel w ith those who have experience of the severalkinds of retail trade, as we before manded, concerning adulteration(which is a matter a kin to this), and w hen they meet they shallconsider what a mount of receipts, after deducting expenses, wil lproduce a moderate gain to the retail trades, and they shall fix inwriting and strictly maintain what they find to be the rightpercentage of profit。 this shall be seen to by the wardens of theagora, and by the wardens of the city, and by the wardens of thecountry. And so retail trade will benefit every one, and do theleast possible injury to those in the state who practise it. When a man makes an agreement which he does not fulfil, unless theagreement be of a nature which the law or a vote of the assemblydoes not allow, or which he has made under the influence of som eunjust pulsion, or which he is prevented from fulfilling againsthis will by some unexpected chance, the other party may go to law w ithhim in the courts of the tribes, for not having pleted hisagreement, if the parties are not able previously to e to termsbefore arbiters or before their neighbours. The class of craftsmen whohave furnished human life with the arts is dedicated to Hephaestus andAthene。 and there is a class of craftsmen who preserve the works ofall craftsmen by arts of defence, the votaries of Ares and Athene,to w hich divinities they too are rightly dedicated. All these continuethrough life serving the country and the people。 some of them areleaders in battle。 others ma ke for hire implements and wor ks, and theyought not to deceive in s uch matters, out of respect to the G ods w hoare their ancestors. If any craftsman through indolence omit toexecute his wor k in a given time, not reverencing the G od who giveshim the means of life, but considering, foolish fellow, that he is hisown God and w ill let him off easily, in the first place, he shallsuffer at the hands of the God, and in the second place, the law shallfollow in a similar spirit. He shall owe to him who contracted withhim the price of the wor ks which he has failed in performing, and heshall begin again and execute them gratis in the given time. When aman underta kes a w ork, the law gives him the same advice which