Talk:Three-tier (computing)

Discussion of Web development versus traditional meanings

I'm pretty sure the traditional and web development meanings of 3-tier are closely related - did they diverge at any certain point? From memory, most introductory web development books (eg. Beginning PHP4, The Cold Fusion 4 Web Application Construction Kit, etc.) around 2000 went over the 3-tier architecture in the introduction or first chapter.

Does the Theory Work?

In a three-tier model, how easily can a web application can be converted to different types of applications?

For example:

Using Jakarta Tomcat <-> Jave 2 Enterprise Edition <-> Mysql

then change it to Apache 2 Web Server <-> PHP <-> Postgre

What type of web application would it be? Well, let's say it is a movie rental web application.

~AT3

Changing the business logic is a pain in the .... Changing PHP for Java Servlets & JSP is very difficult, as the programming is quite diferent. Also, as far as I understand PHP combines both presentation and logic on the same page, whereas a Level 2 JSP implementation implements business logic on servlets and presentation on JSP.

Now regarding the first architecture, it is actually Apache Web Server -> Jakarta Tomcat (Java 2 Enterprise Edition) -> MySQL. The second one is ok. For either of the two, changing for example Apache Web server with MS IIS 4.0 is doable. I have installed IIS with Jakarta. It is also fairly straightfoward to change the database AS LONG AS you use standard ANSI SQL queries.

So basically the theory holds... as long as you don't change the most important part, the business logic. --Threner 03:29, 29 October 2005 (UTC)[reply]

If you use SOA that should take some of the pain away, having all the components at the tiers as stateless independent services that produce and consume SOAP, the theory will work better than, accept you have to go through the pain of making a SOA system.

If you don't the hardest layer to change is generally the business logic, since it can be anything from PHP, ASP, ASP.NET, a Server, JSP, Beans, Cold Fusion, or any number of other custom pieces and will require extensive re-write. If you do the presentation layer correctly that should be easy, and database migraions are not too much of a problem.

Also be warned that my 3-tier system put much of the business logic in the data tier as stored procs. Fun fun fun. Rhooker1236 11:55, 1 September 2006 (UTC)[reply]

Cleanup and merging

For more information on this (and my crazy plans/screw ups) see Talk:Multitier architecture#Cleanup and merging. -- Foofy 07:13, 19 October 2005 (UTC)[reply]

3-Tier is important enough that it deserves its own Wikipedia entry.

Re-merged

I just redid the merge going back the other way, to Three-tier (computing) as the parent, per the apparent consensus in discussion but contrary to the tag direction which I don't think anyone noticed... Georgewilliamherbert 04:39, 26 May 2006 (UTC)[reply]

Comment

I think the merge was needed and was very nice.

Comment

I think Multi-tier should not be merged with 3-tier because multitier can be 3 or four or more tier based upon the user or client requirements.

Comment

I have a number of observations about the content. I think the MVC comparison material may not be correct. It is architecturally permissible for a front-tier entity (view) to directly use a service of a back-tier entity (model), esp for read-only browsing of data and administrative repair of damaged data. I think the 3-tier architecture originates from PARC in 1979 with the MVC design pattern. Although this was initially only a Smalltalk programming pattern, it established a universal concept that all computing functionality breaks down into three fundamental sets of concerns, which should be separated. Everyone at the time was looking at Smalltalk for new concepts, and I think people working in distribution of computing eventually made the obvious application of MVC to their work, although they may not have given credit. The earliest extensive documentation of a fully developed 3-tier distributed software architecture is the OSCA(TM) and INA literature from Bellcore in the early 1990's. The primary thinker behind these projects was John Mills. OSCA described 3-tier distribution of computing. INA added the concept of building blocks (software modules) with contracts (well-formed interfaces) that expose either a service (service contract) or the ability to configure and monitor a service (management contract), and it borrowed the ANSA concept of a middleware "trading service," an automated advertisement and discovery service for contracts that enabled dynamic formation and reformation of distributed systems. The INA concepts are now known generally as Service-Oriented Architecture, which is a natural enabler of 3-tier distributed software. Whereas the Bellcore projects produced around 2,500 pages of somewhat unaccessable distributed computing literature, the content was distilled into a 180 page requirements document by the TeleManagement Forum in 2001. [I have lots of references and other items, but have never really participated in a wikipedia page before. Someone pls tell me what to do! kirk@shrewsbury.com] Does anyone know what became of Microsoft DNA? —The preceding unsigned comment was added by Jkshrews (talk • contribs) 15:35, 13 December 2006 (UTC). Kirk Shrewsbury 12:50, 24 December 2006 (UTC)[reply]

Comment

Multi-tier and three-tier should be combinded. As a student, I have had study questions that make reference to two-tier, three-tier, and n-tier at the same time. Putting it all in one spot makes sense. It is all in one spot in most textbooks, also. Add ing a redirect reference to Multi-tier using the keyword n-tier is helpful, but it needs to be a little clearer that they are the same for CS newbies. Thanks.—The preceding unsigned comment was added by 68.62.46.47 (talk) 19:07, 30 January 2007 (UTC).[reply]