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Lumbago
Norsk Yak Master
3271 Posts |
 Posted - 2004-02-26 : 12:39:43
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| I'm writing some stuff for my boss here (no, not documenting ;) and I began to wonder if I'm actually doing a 2 - or 3-tier application. I basically have my asp/htm, then the stored procedures and the database. What do you guys think? Can I with my integrity intact write 3-tiers? This is btw a cross post from sql-server-performance.com...just wanted a few more opinions...--Lumbago"Real programmers don't document, if it was hard to write it should be hard to understand" |
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nr
SQLTeam MVY
12543 Posts |
Posted - 2004-02-26 : 12:44:47
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| I try never use the term 3 tier (or 2 tier).You could call the service provider another tier. And the physical layer. And ...The important distinction is whether or not connections are bound to the client so I prefer Client server and n-tier.==========================================Cursors are useful if you don't know sql.DTS can be used in a similar way.Beer is not cold and it isn't fizzy. |
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AjarnMark
SQL Slashing Gunting Master
3246 Posts |
Posted - 2004-02-26 : 15:14:55
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| Is the distinction between 2 and 3 tiers important? I'll agree with NR that I prefer the term n-tier.But if you have to count, I would consider stored procedures to be part of the database tier, so if you're going straight from ASP code to the stored procedure that's 2 tiers. If you have some business objects (classes/COM/DCOM) in between, I would think of that as a 3rd tier. I don't count ADO as a tier, although some might be able to argue it is. I would consider SQL commands embedded within the ASP code, instead of using sprocs, to be poor technique, but not fewer tiers.--------------------------------------------------------------Find more words of wisdom at [url]http://weblogs.sqlteam.com/markc[/url] |
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ehorn
Master Smack Fu Yak Hacker
1632 Posts |
Posted - 2004-02-26 : 16:08:46
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| The most common N-tier architecture choice is three part – presentation, business logic, and data. The presentation tier typically encompasses all of the interaction of the user and the application. The goal of the presentation layer is to separate the interface requirements from the rest of the application. The business logic tier encapsulates business logic performed by the application. The business logic layer is typically considered a container of all business intelligence of the application. The Data tier is responsible for the safe keeping of all data required by the application. The Data tier is typically a database management system (DBMS)While I agree with Mark regarding COM/DCOM components, in relation to the Windows DNA N-Tier Application Architecture, typically defined the business logic tier. Logically speaking - this architecture could be considered a 3-tier architecture where ASP facilitate the presentation tier, The sp's encapsulate the business logic and SQL Server houses the data. |
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scullee
Posting Yak Master
103 Posts |
Posted - 2004-02-26 : 16:37:55
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| You could also argue the browser is another tier as well :) |
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nr
SQLTeam MVY
12543 Posts |
Posted - 2004-02-27 : 00:09:52
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| I don't like the concept of a business logic tier as it causes people to think that they need to encapsulate it in a single place whereas some of the logic is best suited to procedural processing and some set based so is best implemented in SPs and procedural code (usually com components) and some in data contsraints.Systems which try to implent in com are usually very slow and prone to deadlocks and those that place it all in SPs end up with complicated sql.==========================================Cursors are useful if you don't know sql.DTS can be used in a similar way.Beer is not cold and it isn't fizzy. |
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byrmol
Shed Building SQL Farmer
1591 Posts |
Posted - 2004-02-27 : 00:21:27
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| I agree with Nigel here, only because SQL DBMS are so poor at even the simpliest business rules. If you can declare them at DDL time, stick them there. I recently managed to jam 8 business rules into a view. If you are good at SQL you would understand it "fairly" easily , but if you are not you'd be scrathcing your head for a while even with the inline comments...Yukon should produce some interesting debates about where and when to stick BLL in the DB....DavidM"SQL-3 is an abomination.." |
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Lumbago
Norsk Yak Master
3271 Posts |
Posted - 2004-02-27 : 00:30:01
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| The problem with this is that people in charge and investors and other people not working in development get very exited when you use terms like "3-tier", "object oriented", and anything that has to do with XML, .NET or Web Services. It sounds really fancy and and they just for some reason love it, allthough they have no clue whatsoever what it really means. And if I'm gonna use those terms I have to be able to defend them in some way and that's also why I'm asking this question. I'm in the process of answering some pre technical due-dilligence questions and I need to use terms that management-teams like to make our company sound appealing. So if any of you guys have suggestions on fancy terms I could use which basically means nothing I'm all ears! And btw; I need them by tomorrow about 2pm GMT, I have to have the answers ready by then :)--Lumbago"Real programmers don't document, if it was hard to write it should be hard to understand" |
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byrmol
Shed Building SQL Farmer
1591 Posts |
Posted - 2004-02-27 : 00:40:55
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| How about...."We will be using a relationally enabled business rules based storage engine, with the capacity for almost infinite queries, supplemented by high speed second tier processing and interfaced by a stateless, scalable and internationally standardised user interface". ;-)DavidM"SQL-3 is an abomination.." |
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Lumbago
Norsk Yak Master
3271 Posts |
Posted - 2004-02-27 : 00:51:42
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| DAMN! You sound like a pro, do you have a history in marketing?? :)--Lumbago"Real programmers don't document, if it was hard to write it should be hard to understand" |
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nr
SQLTeam MVY
12543 Posts |
Posted - 2004-02-27 : 01:22:10
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| >> anything that has to do with XMLA mamanger went on a course and heard about XML. Talked to the developer who was ordered to transfer all data to another system using XML - the manager told the board that this means that the interface will be very flexble and cut maintenance costs.The developer put a tag round the file which was stripped off at the other end so everyone was happy.==========================================Cursors are useful if you don't know sql.DTS can be used in a similar way.Beer is not cold and it isn't fizzy. |
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CtrlAltDel
Starting Member
17 Posts |
Posted - 2004-02-27 : 04:42:28
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I've always considered basic ASP database apps to be 3-tier - the presentation layer (HTML rendered by the browser), business layer (your ASP code), and data layer (the database). Throw in a COM+ application server, and you could claim a four-tier  . Best just stick to calling it n-tier...--David Keaveny |
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ASP, sp's and db = 3-tier...?