外文文献翻译---ADO.Net技术

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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 visiti

2、ng 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

3、the 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 speci

4、ally 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

5、DataSet, 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 defend

6、ing 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 fi

8、nish. 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

9、record 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 t

10、rip 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 , se

11、ek 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 Da

13、taSet 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 pr

14、eserved 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 visi

15、ting 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

16、new 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； M

17、ap_mc=_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 b

18、y the click 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 F

19、orm simplyand 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(coverLay

20、er.Regions_ary 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 demonst

21、rate aspect, this 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 a

22、nd this kind of 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. field ,this kind of method have greater develop potential.