Data Access Technology (Data AccessTecnique) and Data Perception Control (Control)
Tomhornson # (at) #hotmail.com 12/29/2004 in Lushan
Undoubtedly, for more than ten years, in any platform, the data application system has always occupied a lot of proportion in the software system. Therefore, data access technology naturally has received attention. In my experience, the related technologies can be said: 1, Window platform: ODBC, DAO, ADO, ADO.NET 2, Java platform: JDBC
In addition, under the J2EE platform, there are currently techniques commonly used in the Java data application system: DAO and O / R mapping. DAO does not belong to Data Access Technology, which is just a packaging of JDBC, which makes Java database more efficient, refreshing, and the three-layer structure may be possible. DAO is a Pattern. O / R mapping technology is possible for the impact of OO trend, people attempt to interact through more natural object views, so that the overall style of the object access section and the OO system is more integrated, including system analysis, Design and other aspects. O / R mapping technology is a lot, more common include EntityBean, such as Hibernate, JDO, Ibatis, etc. in the day. Especially Hibernate, JDO, there is still not complete EJB3.0, which should be a future mainstream. O / R mapping's impact on J2EE should be relatively far-reaching, but it not only affects the system's data access section, but even has a certain impact on the overall architecture of the system. Of course, these mainly said data (especially rdbms) Apply a centered J2EE system.
On the DOTNET platform of the MS, there is also O / R mapping technology, I am not very clear. I have heard of a NHibernate.
In fact, this article, my goal is not data access technology, but a data perceived control (Control), particularly data perceived controls developed by user web.
I. Data perceived control in Windows desktop applications
I want to use VC, VB, and Delphi compilation, know the data perceived control. For example, the VC's ListControl, VB's DataList control, etc. Of course, there is no magic behind these controls. You tell it that you need to connect to the database, table, column and other information. When the Control is loaded, it uses the information provided to access the database, remove the data, fill it into the Control, is the case. Data perceptual controls can reduce programming burden in a simple database application.
Second, how do we display data? How do you update data to a database? We first obtain data through data access technology such as ADO or ODBC, then use HTML display data. We take the data that needs to be updated via request, and then update the database via ADO or ODBC data access technology.
Here, when you are programming, you have thought about why there is a control of Windows desktop applications in the ASP, or even a data perceived control? Whether you also want to have such a technique, such controls, so your ASP programming is more simple, and efficient.
Third, JSP
But from the most common programming, JSP and ASP, the difference is not big. However, I want to emphasize the jsp of Taglib. What is the benefits of Taglib bring us or tell us what benefits? I think, nothing more than multiplexing some Java logic code, making the page more refreshing, minimizing "pollution" of the JSP page. Personally, taglib's functionality can be done in the form of <%!%> Defined functions. The use of functions can also be reused, which makes the page more refreshed. Someone tells me because taglib uses XML form, so many XML editors can display it via Plugin. I have reserved too much for this statement. Because I have never believed that taglib causes this reason to introduce JSP SPEC. My other idea is that Taglib has a strong extensibility, and this idea has not been confirmed yet. If you say taglib just for multiplexing, beautify the page, then I said that taglib really can say that JSP introduces complex and useless things. Taglib also has no way to program the use of functions in the ASP, but make the programming more trouble.
Four, DOTNET Control
In the (two, ASP) section, we have a wonderful wish: ASP can have controls such as Windows desktop applications, or even data perceived controls? Obviously DOTNET, your wishes are achieved. Talking about it, we have come into contact with the three core topics of this article.
4.1 DOTNET encapsulates C / S interaction, bringing new impacts from Web development
I used to be a long time, JSP, ASP programming is a big reason is that http is non-persistent connection, resulting in the continuous use of requests, verify information, etc. from the Client side, but also use session to users Maintain a long period of session. I feel, these things, really don't make sense, but have to work, and the workload is quite large. The Java field has a project such as Echo, attempting to use the Swing programming style to write webApp. Obviously the development of Web, but it is awkward, this practice is really meaningful? Or is it a good solution? I personally is a nose.
DotNet came out, you only need to program it by the view (view) of Windows desktop applications. What is MAGIC here? It is to encapsulate the information interaction between Client-Server, session, and packaged in the technology that can be seen, and personal feeling is the most perfect.
4.2 JSP Taglib and DotNet WebControl
In the Taglib era, I think why not provide Visuledit for taglib, and provide data perceiveability as a Windows desktop app to simplify development. For example, Display Taglib, I have seen a very good library, if you provide Visuledit, and provide data perception, use it to quickly develop, should be quite good. But why, I didn't see this happening?
DotNet came out, I saw WebControl provided by MS. In my eyes, how can it be taglib so appearance? However, it can be Visual, you can Edit. For small projects, it is undoubtedly, it has absolute competitiveness.
4.3 DOTNET Server-Side-Control's Defects
The technology of MS, including DOTNET, which is simple and fast. This is MS for many years. Therefore, Server-Side-Control is designed to some extent, subject to this inertial thinking. I am currently the problem that it is: its data sensing control can only be perceived by information such as databases, tables, columns and other information. Does not support the induction of Object, Collection, etc., such as ArrayList Instance. And, I know the Java Display Taglib is the ability to feel ResultSet, Collection. You cannot feel objects, collection, then the implementation of the system is hindered. Because you will represent the layer and the database paste. Five, I hope that JSF is
I heard that JSF provides packages such as Visual, C / S interaction, and ASP.NET very similar. I haven't learned this, I'm
I hope to bring us surprises.
Sixth, JDBC, ADO.NET, O / R MAPPING
Needless to say, ADO.NET is a new generation, not a JDBC, but the force of the Javavopensource community
Quantity, not underestimation. Since it, in the J2EE field, give you an ADO.NET, I think you will still choose the O / R mapping tool for the Hibernate stream to do development.
Note: The idea of this article is basically only a probably idea. Because I have a limited understanding of DOTNET. Also, how to develop Taglib's Visuledit? DOTNET-Server-Side-Control to support physical LIST, Collection, etc. Doing this means that what happens in other joints? Even if it is realized, what extent? These have no in-depth thinking and discussion. In the future, I have time to say.
Revised record: First: 12/29/2004
