【正文】 Think of what the application is for and then list what you want it to do. From this reasoning, you should get the following list: Paradox。Microsoft FoxPro。Oracle Personal Edition 7i or 8i。用戶將怎樣容易展示這信息？ 很多時間，這種限制出現(xiàn)在一個已經(jīng)存在數(shù)據(jù)的數(shù)據(jù)庫引擎的一個函數(shù)和它安全地 支持能多少數(shù)據(jù)。如果你堅持改變 just one more thing 應(yīng)用程序?qū)⒂肋h完成不了。嗯，一個好的設(shè)計和測試關(guān)系到這個問題。 報告精品選集想法的每類型完全依賴件報告的工具用來創(chuàng)造并且展示報告。 但是你 必須允許用戶選擇他們想要的輸出格式。國籍 查詢界面在大多數(shù)應(yīng)用程序中是最基本的界面，所以你可以使用如何程序的設(shè)計觀念，圖 3 顯示的是簡單應(yīng)用程序的搜索界面。 特殊查找 接下來該軟件要實現(xiàn)的是對數(shù)據(jù)庫中特定輸入的查詢的功能。有些軟件把名字作為索引，使得用戶信息不能被修改。 雖然數(shù)據(jù)的輸入和顯示直涉及到兩個方面的，每一個操作只需要一點操作，第一個窗體可以使用戶輕松的輸入信息。打印不同的報表 接下來不是做巨大的，需要合作開發(fā)的應(yīng)用程序，而是那些較小的，個人的。它也將提供不同格式的報告并且允許用戶搜尋適合一特別的人的數(shù)據(jù)庫。然后，應(yīng)用完成，改變 ODBC 連接對更大，基于服務(wù)器版本。 大部分大型數(shù)據(jù)庫服務(wù)器提供將在獨立 PC 機上運轉(zhuǎn)的版本。 本地數(shù)據(jù)庫一般用于單個用戶的應(yīng)用例如支票本，通訊錄，以及個人信息經(jīng)理。dBase。Microsoft Access。使用這些標(biāo)準(zhǔn)的好處如下： 高性能數(shù)據(jù)的使用 在不降低性能的前提下提供了任何 應(yīng)用或者組成部分支持現(xiàn)行的擁護連接的功能； 可靠性 降低了在 PC 上支持的部件； 以及廣泛的工業(yè)支持 包括微軟公司的很多供應(yīng)商已經(jīng)宣布對 UDA 標(biāo)準(zhǔn)的支持了。 微軟公司從發(fā)展策略考慮，允許任何公司或者數(shù)據(jù)庫訪問相同方法。 應(yīng)用程序的類型將影響你選擇的數(shù)據(jù)庫類型。Microsoft FoxPro。 理解兩者的區(qū)別將幫助你選擇你的需要的正確的數(shù)據(jù)庫。 但是 UDA 是什么？通用數(shù)據(jù)存取微軟公司發(fā)展確定并且交付使用 的適合未來的應(yīng)用開發(fā)的標(biāo)準(zhǔn)的一個平臺，應(yīng)用和工具。 預(yù)計，微軟公司計劃為有利于 OLE DB 和 UDA 標(biāo)準(zhǔn)發(fā)展而逐步淘汰 ODBC。 訪問這些數(shù)據(jù)庫不要求 PC 機安裝任何其他軟件被，它也不需要關(guān)于怎樣操作這些數(shù)據(jù)庫的專門知識。 ODBC 數(shù)據(jù)庫分成兩個主要種類： 在一單個 PC 上運行的和一個是一個巨大的模塊，運行在性能強的具有巨大磁盤空間的計算機 (服務(wù)器 )。 and 我們必須鼓勵的對應(yīng)用程序的描述如下： 個人地址 /電話簿 這應(yīng)用程序?qū)⒂妹纸壎郑刂泛碗娫捥柎a。這是在開發(fā)新版本的時候要考慮的。好，我們已經(jīng)選擇了你將要建立的應(yīng)用程序，現(xiàn)在你要列出它將提供哪些功能，仔細考慮這個程序是為什么開發(fā)的和你該做什么，因為以上原因，你需要理解以下幾條： 表格 1 列舉你能為這類應(yīng)用使用的數(shù)據(jù)元素。 在這些功能模塊代碼之間有一定的聯(lián)系，然而，別的只是數(shù)據(jù)之間的聯(lián)系。前一條 配偶名字 但是這個目錄采用什么格式呢？一些人將想要打印一個名字和編號存放在他們的公文包或者錢包。這種方法可以讓用戶自行設(shè)計一些不同的標(biāo)準(zhǔn)報表，那樣用戶就可以根據(jù)自己需要修改得到不同的版本。 當(dāng)然，這種功能同時有它的問題和要求。這類發(fā)行真的 取決于是否你正計劃出售應(yīng)用程序和什么時候做好進入市場的準(zhǔn)備。 你在開發(fā)應(yīng)用程序確定的第 2 個限制是多少數(shù)據(jù)才太多，雖然你想要開發(fā)相當(dāng)靈活的程序，為用戶提供太多靈活性通常以誤差的形式產(chǎn)生不良后果并且丟失數(shù)據(jù)為代價的。 and Wide industry support – Many vendors including Microsoft have already announced support for the UDA standards. In previous releases of Visual Basic, you needed to choose from either DAO (local) access methods to data or RDO (remote) access to data. Now, with the support of UDA , Visual Basic has a third method for data access called ADO, or ActiveX Data Objects. This allows you to bine the different ways of accessing data into one set of programming calls and objects. ADO works in conjunction with OLE DB and ODBC to provide access to one database you might be working with. Getting forward, Microsoft plans to phase out ODBC in favour of OLE DB and the UDA standards. However, for the near future, DAO and RDO, as well as ODBC, will still be supported to allow developers to slowly move up to the new standards of data access. Local Databases Local databases are generally much smaller than the remote type of database. The following databases fall into this category: Sybase。Print different types of reports。Update。Print. Then again, some applications bine the Add form and display/modify form into one single form and task by including one more mand button on the form to request the add task. Searching for a Particular Name The next task in this application will provide the ability to search the database for a particular entry. Now, when you use the Explorerstyle interface, it does not make much sense to search by the person’s last name. However, you might need to find someone in the database in many other ways, including the following Another way is to add search capability to the report selection. Each type of report selection ideas depends pletely on the reporting tool being used to create and display the reports. Allowing for Different Users Many database applications can work with multiple copies of the database. This allows more than one person in the household to use the application, yet have their own private address/phone database. You can go even further by requiring a password to allow access to the database when it’s first opened. This type of process is usually available from the main application menu or toolbar as shown in Figure 3. Figure 3 – Giving users the ability to select different databases to use in the application. Of course this capability es with it’s own problems and requirements. The most important one that you need to apply with the application is an empty copy of the database that will be used to create each different working copy that users want. Easily Maintaining the Application What does maintenance really mean to users? The only thing they’re interested in is whether the application will work every time they use it. Well, a good design and good testing should take care of this concern. But what if something goes wrong on their puter and they lose the database files, or they accidentally delete the files? Your application must allow users to create backup files of the database files so that if the unthinkable happens, they can simply restore their data from the backup copy. Referring back to multiple databases, this backup system will have to recognise which database is being backed up. Setting the Limits Setting the limits of an application covers two distinct areas of the design process. When designing an application, you’ll probably develop a list of functions and features that you want to see in the application but