【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(duì)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(duì)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(duì)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(cè)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(duì)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】 A poor, bare, miserable room it was, with broken windows, no fire, ragged bedclothes, a sick mother, wailing baby, and a group of pale, hungry children cuddled under one old quilt, trying to keep warm. How the big eyes stared and the blue lips smiled as the girls went in. Ach, mein Gott! It is good angels e to us! said the poor woman, crying for joy. Funny angels in hoods and mittens, said Jo, and set them to laughing. In a few minutes it really did seem as if kind spirits had been at wor k there. Hannah, who had carried wood, made a fire, and stopped up the broken panes with old hats and her own cloa k. Mrs. March gave the mother tea and gruel, and forted her with promises of help, while she dressed the little baby as tenderly as if it had been her own. T he girls meantime spread the table, set the children round the fire, and fed them like so many hungry birds, laughing, talking, and trying to understand the funny broken English. Das ist gut! Die Engel kinder! cried the poor things as they ate and warmed their purple hands at the fortable blaze. T he girls had neve r been called angel children before, and thought it very agreeable, especially Jo, who had been considered a `Sancho39。 ever since she was born. That was a very happy breakfast, though they didn39。t ge t any of it. And when they went away, leaving fort behind, I think there were not in all the city four merrier people than the hungry little girls who gave away their breakfasts and contented themselves with bread and milk on Christmas morning. That39。s loving our neighbor better than ourselves, and I like it, said Meg, as they set out their presents while their mother was upstairs collecting clothes for the poor Hummels. Not a very splendid show, but there was a great deal of love done up inster an encouraging pat on the shoulder as they parted for the day, each going a different way, each hugging her little warm turnover, and each trying to be cheerful in spite of wintry weather, hard work, and the unsatisfied desires of pleasure loving youth. When Mr. March lost his property in trying to help an unfortunate friend, the two oldest girls begged to be allowed to do something toward their ow n support, at least. Believing that they could not begin too early to cultivate energy, industry, and independence, their parents consented, and both fell to work with the he arty good will which in spite of all obstacles is sure to succeed at last. Margaret found a place as nursery governess and felt rich with her small salary. As she said, she was `fond of luxury39。, and her chief trouble was poverty. She found it harder to bear than the others because she could remember a time when home was beautiful, life full of ease and pleasure, and want of any kind unknown. She tried not to be envious or discontented, but it was very natural that the young girl should long for pretty things, gay friends, acplishments, and a happy life. At the Kings39。 she daily saw all she wanted, for the children39。s older sisters were just out, and Meg caught frequent glimpses of dainty ball dresses and bouquets, heard lively gossip about theaters, concerts, sleighing parties, and merrymakings of all kinds, and saw money lavished on trifles which w ould have been so precious to her. Poor Meg seldom plained, but a sense of injustice made her feel bitter toward everyone sometimes, for she had not yet learned to know how rich she was in the blessings which alone can make life happy. Jo happened to suit Aunt March, who was lame and needed an active person to wait upon her. The childless old lady had offered to adopt one of the girls when the troubles came, and was much offended because her offer was declined. Other friends told the Marches that they had lost all chance of being remembered in the rich old lady39。s will, but the unworldly Marches only said... We can39。t give up our girls for a dozen fortunes. Rich or poor, we will keep together and be happy in one another. The old lady wouldn39。t speak to them for a time, but happening to meet Jo at at a friend39。s, something in her ical face and blunt manners struck the old lady39。s fancy, and she proposed to take her for a panion. This did not suit Jo at all, but she accepted the place since nothing better appeared and, to every one39。s surprise , got on remarkably well with her irascible relative. There was an occasional tempest, and once Jo marched home, declaring she couldn39。t bear it longer, but Aunt March always cleared up quic kly, and sent for her to e back again with such urgency that she could not refuse, for in her heart she rather liked the peppery old lady. I suspect that the real attraction was a large library of fine books, which was left to dust and spiders since Uncle March died. Jo remembered the kind old gentleman, who used to let her build railroads and bridges with his big dictionaries, tell her stories about queer pictures in his Latin books, and buy her cards of gingerbread whenever he met her in the street. The dim, dusty room, with the busts staring down from the tall bookcases, the cozy chairs, the globes, and best of all, the wilderness of books in which she could wander where she liked, made the library a region of bliss to her. The moment Aunt March took her nap, or was busy with pany, Jo hurried to this quiet place, and curling herself up in the e asy chair, devoured poetry, romance, history, travels, and pictures like a regular bookworm. But, like all happiness, it did not last long, for as sure as she had just reached the heart of the story, the swee test verse of a song, or the most perilous adventure of her traveler, a shrill voice called, Josy phine! Josy phine! and she had to leave her paradise to wind yarn, wash the poodle, or read Belsham39。s Essays by the hour together. Jo39。s ambition was to do something very splendid. What it was, she had no idea as yet, but left it for time to tell