外文文獻(xiàn)翻譯

1、 英文一原文：ado. net technology ado. net is designed for solving the web and program problem about the distribution application by microsoft. as a kind of visit frame of database, ado. net can handle the n layers data architecture which doesnt join that web application program requires, thus when visitin

2、g the database of sql server, superior performance has gotten extensive application. this paper discusses for this. i.the major object of ado.net. many objects in ado.net is similar to the object function in ado , but the function of the object in ado.net is more powerful. at the same time, except t

3、he objects of the connection, parameter and command , ado. net also add a lot of new object and program melt interface, such as dataset, dataview, dataadapter, datareader and datasetcommand etc.it make more simple to operate the database. i.a dataset object: dataset is the core of ado.net, is specia

4、lly used to handle the data which is read out from the stock , and keep it in local memory as away from line. we can use identical way to operate the data which is got from the different data source, the behavior of dataset is consistent whatever the base layer database is sql server or oracle. in d

5、ataset, it can contain arbitrary quantity of datatable, and every datatable is in correspondence with table or view in darabase. generally speaking,a corresponding datatable is a set of a group of datarow and datacolumn for the data sheet of elephant.datatable can take the responsibility for defendi

6、ng each data trip to retain its initial state and current state, with the concurrent that solves database visit problem. ado.net reduce the pressure of being away from line to join pattern decreasing for data server. i.b datareader object: when looking over mass data with the way that glanced over ,

7、 it will occupy plenty of memories and cause performance to drop. for instance,when a link (connection ) reads the record of 1000 lines of database by using the traditional ado recordset ,it must give this link memory distribution for this 1000 lines of record untill the life period of this link fin

8、ish. if there are many users carrying out the same operation for same computer at the same time,the memory will be used out. to solve these problems, dotnet frame has offered datareader object, from database,it return a read-only string, which can roll downward only to flow ( strem ), and exists a r

9、ecord every time only in courently. i.c dataview object: dataview object representative one datatable approach by looking over , it is to put data in order with the form of form that what data acquiesce in look over way, and the order of data that put data in order follow the order taking out the tr

10、ip that put litre and the fence position of row order in order from database data sheet, usually it is concerned with the sort order or reduce power in inquiring string when design the database .ado. net offer the way that has elasticity very much to let user use row order and condition filter , see

11、k etc. property way of looking over of defining difference , so, edit and glance over data or show the data in datatable .for instance ,we can establish a dataview object, then designate with with default look over ( defaultview ) different row order way, or also can use condition filter ( filter )

12、look over the partial data in data sheet. this kind of way can tie two above control items to a same data sheet, but what show is thay the different data. i.d dataadapter object: ado. net establish and initialize data sheet through dataadapter, so as to keep the data in the memory combining with dat

13、aset object. dataadapter object can hide the details that links up with connection and command. dataadapter object allow to put the data to the data source ( datasource )which gets from dataset object.it can also take out data from data source. by the same way,it can also operate the bottom data pre

14、served by adding ,deleting or modifing. ii.visit database in joining ii.a the analysis of a example which visit the database of sql server in ado.net technology abstract with the thorough that applied along with distributed database, permanent database connection consumes resource fairly. when visit

15、ing the database of sql server, it can solve this problem perfectly with ado . net technology . this paper primarily discusses net the major object of ado.net, and analyse the course of visiting sql server furtherly. keyword ado. net visit xml independently drawing the bottom graph of the map, add n

16、ew picture layer according to the fuction of defined , setting picture layer visibility and so on: / / constructs function function flashmap ( width: number, height: number, geo_x: number, geo_y: number ) layerscount = 0; layers=new array();stagewidth=width;stageheight=height;x=geo_x;y=geo_y;map_mc=

17、_root.createemptymovieclip(map_mc,0);map_mc.createemptymovieclip(map_mc,-200);/create object map = new flashmap( stagewidth, stagehight, mapx, mapy); /loading map function initmap () map. drawmap (); ii.b the information inquiry of the map datas:the inquiry of datais was mainly carried out by the cl

18、ick of mouse and the choose of frame on the flash which is loaded with the line,the point and the side of layer .we can see whether the field of the mouse choosing contain the object data through querying the courrent layer of the picture ,if exiting,to return the inquiry result in the new form simp

19、lyand show it to the user. the code of the script of mouse option:function select ( ) var selectedregion: array; selectedregion=new array();for(j=0;jmap.layerscount;j+)var coverlayer:maplayer=map.layers j;for(i=0;iconverlayer.regions_ary.length;i+)var region:mapregion=mapregion(coverlayer.regions_ar

20、y i);if(region.isinregion(_root._xmouse,_root._ymouse)selectedregion.push(coverlayer);selectedregion.push(region); iii. the practice of concluding remarks proves , in database the campus geography information that doesnt request too high, development data to lose comparatively demonstrate aspect, th

21、is is a kind of practical feasible , development the easy method with cheap cost. besides, with the network electronic map colour of this kind of method produce completion, it is rich , content much shape, if wander the network electronic map plane of fictitious realistic technology and this kind of

22、 produce method that combines and can come true the environment of campus geography with space wander. this kind of network electronic map demonstrate effect is traditional gis software which is nearly impossible to reach , in campus situation demonstrate and construct sub-district demonstrate etc.

23、field ,this kind of method have greater develop potential. 中文一譯文：ado.net技術(shù) ado.net 是microsoft 為解決web 和分布式應(yīng)用程序問(wèn)題而設(shè)計(jì)的。作為一種數(shù)據(jù)庫(kù)訪問(wèn)框架, ado.net 能處理當(dāng)今n 層的web應(yīng)用程序所要求的非連接數(shù)據(jù)體系結(jié)構(gòu), 因而在訪問(wèn)sql server數(shù)據(jù)庫(kù)時(shí), 性能優(yōu)越, 得到了廣泛應(yīng)用。本文對(duì)此進(jìn)行了討論。一、ado.net 的主要對(duì)象ado.net 中有很多對(duì)象與ado 中的對(duì)象功能相似, 但ado.net 中對(duì)象的功能更強(qiáng)大。同時(shí), 除connection、paramete

24、r、command對(duì)象外ado.net 還添加了許多新的對(duì)象和程序化接口, 如dataset 、dataview、dataadapter、datareader、datasetcommand 等,使得對(duì)數(shù)據(jù)庫(kù)的操作更簡(jiǎn)單。1、dataset 對(duì)象: dataset 是ado.net 的核心, 是專門用來(lái)處理從數(shù)據(jù)存儲(chǔ)中讀出的數(shù)據(jù), 并以離線方式存在于本地內(nèi)存中?？梢允褂孟嗤姆绞絹?lái)操作從不同數(shù)據(jù)來(lái)源取得的數(shù)據(jù), 不管底層的數(shù)據(jù)庫(kù)是sql server 還是oracle, dataset 的行為都是一致的。在dataset 中可以包含任意數(shù)量的datatable, 且每個(gè)datatable 對(duì)應(yīng)一

25、個(gè)數(shù)據(jù)庫(kù)的table 或view。一般來(lái)說(shuō), 一個(gè)對(duì)應(yīng)datatable 對(duì)象的數(shù)據(jù)表就是一組datarow 與datacolumn 的集合。datatable 會(huì)負(fù)責(zé)維護(hù)每一筆數(shù)據(jù)行保留它的初始狀態(tài)和當(dāng)前的狀態(tài), 以解決數(shù)據(jù)庫(kù)的并發(fā)訪問(wèn)問(wèn)題。ado.net 的離線連接模式減少了對(duì)數(shù)據(jù)服務(wù)器的壓力。2、datareader 對(duì)象: 當(dāng)以瀏覽的方式查看大量數(shù)據(jù)的時(shí)候,會(huì)占用大量?jī)?nèi)存, 導(dǎo)致性能下降。例如, 一個(gè)鏈接(connection) 用傳統(tǒng)的ado recordset 對(duì)象去讀1000 行數(shù)據(jù)庫(kù)的記錄, 則必須為這1000 行記錄將內(nèi)存分配給這個(gè)鏈接直至這個(gè)鏈接的生命周期結(jié)束。如果有多個(gè)用

26、戶在同一時(shí)間對(duì)同一計(jì)算機(jī)進(jìn)行同樣的操作, 則機(jī)器內(nèi)存將被過(guò)度使用。為了解決這些問(wèn)題, dotnet 框架提供了datareader 對(duì)象, 從數(shù)據(jù)庫(kù)返回一個(gè)只讀的、僅能向下滾動(dòng)的串流(strem), 而且當(dāng)前內(nèi)存中每次僅存在一條記錄。3、dataview 對(duì)象: dataview 對(duì)象代表一個(gè)datatable 的數(shù)據(jù)查看方式, 數(shù)據(jù)默認(rèn)的查看方式是將數(shù)據(jù)以表格的形式排列, 且數(shù)據(jù)排列的順序遵循從數(shù)據(jù)庫(kù)數(shù)據(jù)表中取出數(shù)據(jù)時(shí)行排列的順序, 通常和設(shè)計(jì)數(shù)據(jù)庫(kù)時(shí)的sort order 或在查詢字符串中指明排序的欄位、升降冪有關(guān)。ado.net 提供非常有彈性的方式以供用戶利用排序、條件過(guò)濾、查找等特性

27、來(lái)定義不同的查看方式,從而編輯、瀏覽數(shù)據(jù)或顯示datatable 中的數(shù)據(jù)。例如, 可以建立一個(gè)dataview對(duì)象,然后指定和以缺省的查看(defaultview) 不同的排序方式, 或者也可以使用條件過(guò)濾(filter) 只查看數(shù)據(jù)表中的部分?jǐn)?shù)據(jù)。這種方式，可以將兩個(gè)以上的控制項(xiàng)綁定到同一個(gè)數(shù)據(jù)表, 但顯示的是不同的數(shù)據(jù)。4、dataadapter 對(duì)象: ado.net 通過(guò)dataadapter 對(duì)象建立、初始化數(shù)據(jù)表, 從而和dataset 對(duì)象結(jié)合起來(lái)在內(nèi)存中存放數(shù)據(jù)。dataadapter 對(duì)象能隱藏和connection、command 對(duì)象溝通的細(xì)節(jié)。dataadapter

28、對(duì)象允許將dataset 對(duì)象中的數(shù)據(jù)保存到數(shù)據(jù)來(lái)源(datasource) , 也可以從數(shù)據(jù)來(lái)源取出數(shù)據(jù)。同理, 也可以對(duì)底層數(shù)據(jù)保存體進(jìn)行數(shù)據(jù)的添加、刪除或修改操作。二、數(shù)據(jù)庫(kù)連接訪問(wèn)ado.net 訪問(wèn)sql server數(shù)據(jù)庫(kù)的實(shí)例分析 摘要 隨著分布式數(shù)據(jù)庫(kù)應(yīng)用的深入, 永久的數(shù)據(jù)庫(kù)聯(lián)接是相當(dāng)耗費(fèi)資源的。在訪問(wèn)sql server數(shù)據(jù)庫(kù)中, 采用ado.net 技術(shù)可以完美地解決這個(gè)問(wèn)題。本文討論了ado.net 的主要對(duì)象, 并深入分析了其訪問(wèn)sql server 的過(guò)程。 關(guān)鍵字 ado.net 獨(dú)立訪問(wèn)xml據(jù)其定義的函數(shù)繪制地圖底層圖形、添加新圖層, 設(shè)置圖層的可見性等等:/

29、構(gòu)造函數(shù)function flashmap (width:number, height:number,geo_x:number,geo_y:number) layerscount = 0;layers = new array () ;stagewidth = width;stageheight = height;x = geo_x;y = geo_y;map_mc=_root.createemptymovieclip ( map_mc ,0) ;map_mc.createemptymovieclip ( map_mc ,- 200) ;/創(chuàng)建實(shí)例map = new flashmap (stag

30、ewidth, stagehight, mapx, mapy) ;/裝載地圖function initmap () map.drawmap () ;2.4 地圖數(shù)據(jù)的信息查詢: 對(duì)于flash 上加載的地圖各圖層的點(diǎn)、線、面數(shù)據(jù)的查詢主要是鼠標(biāo)的點(diǎn)選和框選來(lái)實(shí)現(xiàn)的, 通過(guò)查詢當(dāng)前圖層中是否有實(shí)體對(duì)象數(shù)據(jù)包含在鼠標(biāo)選擇范圍內(nèi), 若存在則返回簡(jiǎn)單查詢結(jié)果在新窗口中顯示給用戶。鼠標(biāo)選擇的腳本代碼為:function select () var selectedregion:array;selectedregion=new array () ;for (j=0; jmap.layerscount; j

31、+) var coverlayer:maplayer = map.layers j ;for (i=0; iconverlayer.regions_ary.length; i+) var region:mapregion = mapregion ( coverlayer.regions_ary i) ;if ( region.isinregion ( _root._xmouse, _root._ymouse) )selectedregion.push (coverlayer) ;selectedregion.push (region) ;3.結(jié)束語(yǔ)實(shí)踐證明, 在數(shù)據(jù)庫(kù)要求不高、動(dòng)態(tài)數(shù)據(jù)較少的校

32、園地理信息展示方面, 這是一種切實(shí)可行、開發(fā)容易、成本低廉的方法。此外,采用這種方法制作完成的網(wǎng)絡(luò)電子地圖色彩豐富, 內(nèi)容多樣, 如果把虛擬現(xiàn)實(shí)技術(shù)與這種制作方法的網(wǎng)絡(luò)電子地圖結(jié)合起來(lái), 就可以實(shí)現(xiàn)校園地理環(huán)境的平面漫游和空間漫游。這種網(wǎng)絡(luò)電子地圖的展示效果是傳統(tǒng)gis 軟件很難達(dá)到的, 在校園地理位置展示和建筑小區(qū)展示等領(lǐng)域這種方法具有較大的發(fā)展?jié)摿?。英文二原?the data binding technology in my project,i need to show the data from the database,so i need to use the data bindin

33、g technology which microsoft company support.in the following ,lets discuss it together.if you are familiar with classic asp, the declarative data binding syntax introduced in asp.net will be familiar to you even though the functionality is vastly different. data binding expressions are the code you

34、 see between characters in an aspx file. the expressions allow you to easily bind controls to data sources, as well as properties, expressions, and results from method calls exposed by the page. while this feature is easy to use, it often causes some confusion about what is allowed and whether it sh

35、ould be employed.data binding basicsdata binding expressions link asp.net page properties, server control properties, and data sources when the pages databind method is called. you can place data binding expressions on the value side of an attribute/value pair in the opening tag of a server control

36、or anywhere in the page. all data binding expressions, regardless of where you place them, must be contained between characters.when used with data controls (like repeater, datagrid, and so forth), the expression parameter is usually a column name from the data source. however, as long as it returns

37、 a value, any valid expression may be used. likewise, the same syntax may be used outside list controls. this includes displaying values on the page or populating control attributes.container.dataitem is a runtime alias for the dataitem bound to a specific item. it maps to an individual item from th

38、e data source like one row from a database query or an individual element from an array. the actual data type for the dataitem is determined by the data source. so, if youre dealing with an array of integers, the dataitem will be an integer.the following list provides a quick review of the vb.net sy

39、ntax for various scenarios:-an array of string values is returned. -the specific field from a dataview container is returned. -the specific string property value of data source is returned. -returns a property value converted to its string representation. when youre using c#, the syntax is a bit dif

40、ferent. the following list includes the corresponding c# code for each line in the previous list. notice the basic syntax is the same, but it changes when property values are returned and converted to the appropriate data type. syntax is consistent when working with page level properties and methods

41、. the syntax remains the same as long as string values are returned. the following list provides some examples:-the value for a page level property is returned. asp:listbox id=lstvalues datasource= runat=server-the value retrieved from the page level property (array, collection of objects, etc.) is

42、bound to the data control. -the value of the page level object property is displayed. -the value returned from the page method is displayed. you may use individual values (albeit properties, method return values, and so forth) on a page using the following syntax:the c# code in listing a demonstrate

43、s data binding in an asp.net web form. it selects employee names and telephone numbers from the sql server northwind employees table. the values from the query are displayed via an asp.net repeater control. the column values are inserted via data binding, and the forms window title is populated usin

44、g a method call. in addition, the itemindex property of the dataitem is used to display a row number. the itemindex property begins with zero, so one is added before it is displayed.listing b contains the equivalent vb.net code. the main difference is the use of parentheses as opposed to brackets in

45、 c#. also, the casting of the rows is not necessary with vb.net.using the contain.dataitem object can be tedious, since you must be aware of the data type and convert it accordingly for use. microsoft does provide the databinder class to further simplify development.microsoft documentation (on msdn)

46、 states the databinder class uses reflection to parse and evaluate a data binding expression against an object at runtime. this method allows rad designers, such as visual studio .net, to easily generate and parse data binding syntax. this method can also be used declaratively on a web forms page to

47、 simplify casting from one type to another.you can use the eval method of the databinder class to make .net do the heavy lifting when using data values in an asp.net page. the eval method accepts the previously covered container.dataitem object; it works hard to figure out the details of the field i

48、dentified in the expression and displays it accordingly. it has the following syntax:databinder.eval(container.dataitem, field name, optional formatting)using this syntax, you could rewrite the first example to use databinder.eval to look like the c# code in listing c. listing d contains the equival

49、ent vb.net code.the databinder.eval approach is great as it pushes work to the system. on the other hand, you should use it with caution, since time and resources are consumed as the system locates the element and determines its object/data type.plenty of optionsdata binding makes it relatively simp

50、le to include data in asp.net pages. there are various data binding options available, which include: binding the data to a control and allowing it to decide how it is presented, or choosing declarative data binding to control presentation within the asp.net page. in the end, it comes down to your p

51、reference, but it is great to have options.中文一譯文：數(shù)據(jù)捆綁技術(shù) 在我的項(xiàng)目中，我需要從數(shù)據(jù)庫(kù)顯示數(shù)據(jù)，因此我使用數(shù)據(jù)捆綁的技術(shù) 它是由微軟公司支持的。如下,我們一起來(lái)談?wù)撍?如果你熟悉經(jīng)典asp，在asp.net介紹申明數(shù)據(jù)捆綁的句法與它在功能是有很大的不同。 數(shù)據(jù)捆綁的表達(dá)方式：就是能在aspx文件中以在此形式（）之間出現(xiàn)的代碼。 這種表達(dá)方式允許你把控件很容易地綁定到數(shù)據(jù)源，連同屬性，語(yǔ)法，結(jié)果值同時(shí)在方法調(diào)用時(shí)在頁(yè)面中顯示。 當(dāng)這些特性輕松的被使用時(shí)，由于它是否被允許能夠被調(diào)用而經(jīng)常造成一些的混亂。數(shù)據(jù)捆綁的基本原則：當(dāng)databind方法被調(diào)用時(shí)，數(shù)據(jù)就捆綁到asp.net的控件屬性，數(shù)據(jù)源。