[evry1falls]

I've took an assignment from some company and the requirements document said :

Quote

The program should use a three-tiered structures with presentation , business and persistence classes ??

I've no idea what is that mean.
i'm almost finished with the software design, but did not start coding till now, please if anyone knows what is that suppose to mean ..... tell me right a way ....
Thanx

[BobRodes]

Well, if you don't know what three-tier architecture is, and the requirements document specifies it, then you aren't almost finished with the software design. You're just getting started, and have some all-nighters to pull. Good luck! Maybe your design intuitively runs along these lines anyway.

Here's an overview. Presentation means whatever you show people. Business objects encapsulate business rules. Persistence classes just means the same as data classes: persistence means permanent storage (basically). So, separate out what sort of classes are involved in the UI. Use those classes to call the business object's methods; use the business object to call data layer methods that get and store data.

Business rules are things like "All new employees must go through a de-lousing procedure as part of the new hire process." This would imply an employee object with a Hire method. Part of the behavior of this method would be to store a "de-lousing date" date in the Hire table of the database (note that the Employee table would probably be a different table, since an employee could leave and get rehired and have to get de-loused again, but his information might stay the same).

So, the UI (presentation) might have a screen where you entered new hire information, and then a save button. The save button would NOT call save methods in the database directly. Rather, it would call this Hire method, which would itself call save methods in the database. This way, the Hire method could make sure that the data about to be entered conformed to business rules ("is there a de-lousing date, if not, send an error", for example).

UI displays and inputs data, business validates data inputs and authorizes data displays, data stores and serves up data.

Does that help a bit? Googling "three-tier architecture" will give you a wealth of further information.

[modi123_1]

Sounds like MV-V-M or MVC... either way that will alter your 'design phase' substantially.. though I do find it some what odd you took a job from a company and were not clear on all the requirements.

https://en.wikipedia..._View_ViewModel

edit - ah.. looks like Bob got here before I could comeback to it.

[evry1falls]

Googling did not give me anything, but your words were quit enough for me.
But what you explained can not imply to the software assigned to me, coz the contractor was clear about how many forms and buttons and methods to use in the (Requirements Document).
But i think he wants the minimum of what you have just said, for example :
instead of ("All new employees must go through a de-lousing procedure as part of the new hire process") he may want a rule written in code form to control ("who should get discount and who should not"), coz also he was clear about not having and kind of databases .... Thanx again for your help .

BTW, out of this topic, please recommend me a forum discusses I\O in VB2010 OR VB2008 ...

[modi123_1]

Quote

BTW, out of this topic, please recommend me a forum discusses I\O in VB2010 OR VB2008 ...

Typically those fall in the VB.NET forums.

[evry1falls]

Why no-one ever rates me .... ?!

[modi123_1]

Quote

Why no-one ever rates me .... ?!

Ah, what?

[BobRodes]

modi123_1, on 07 May 2012 - 09:09 AM, said:

Sounds like MV-V-M or MVC... either way that will alter your 'design phase' substantially.. though I do find it some what odd you took a job from a company and were not clear on all the requirements.

https://en.wikipedia..._View_ViewModel

edit - ah.. looks like Bob got here before I could comeback to it.

There's actually a difference between three-tier and MVC architecture. In three-tier (or n-tier, but let's not complicate) architecture, the business layer handles communications both with the presentation layer and the data layer; presentation never directly interacts with data. In MVC, View sends updates to Controller which updates Model which updates View. So, the three-tier topology is linear whereas the MVC topology is triangular.

[modi123_1]

Ah.. everyone in these parts seem to use MVC and three-tier interchangeably.

[BobRodes]

evry1falls, on 07 May 2012 - 11:34 AM, said:

Why no-one ever rates me .... ?!

Don't take it personally. I've looked over your 20 posts, and in those you answer one question and ask 19. You don't get upvoted for asking questions, you get upvoted for answering them in helpful fashion. While I appreciate your upvoting people who help you, a lot of people don't do that. As you can see, I have posted over 1800 answers on here with no questions, and my rep votes are somewhat less than 300. Modi has posted over 14,000 answers and has a rep of about 3350. And you are asking for a rep of 1 or better for one answer? Have a look around.

[tlhIn`toq]

evry1falls, on 07 May 2012 - 07:40 AM, said:

I've took an assignment from some company and the requirements document said :

Quote

The program should use a three-tiered structures with presentation , business and persistence classes ??

I've no idea what is that mean.

Then why on Earth did you take the job? How did you figure the pay if you had no idea what the work involved? How would you know to bid 4 or 400 hours?

Accepting contracts that you KNOW you aren't qualified for is going to ruin your on-line reputation in a heart-beat. Do you want to make it even harder on yourself to find paying work?

You can do anything you like, it won't affect us but I would HIGHLY recommend you do not do something this silly again if you want to stay in this career field. Employers search those job sites... they search Google... They search Facebook... Hell they check your credit rating now days... If you ruin your reputation you'll have a hard time finding anything that doesn't involve the phrase "Do you want fries with that?"

That doesn't even begin to cover how unprofessional it is to tell an employer that you'll take the contract knowing you can't do the job. That employer probably has commitments and deadlines. You could have just cost someone thousands of dollars in late delivery charges. Possibly made someone in that company look REALLY bad and jeopardized their job.

Additionally that company may choose to not put work out for bid again because they see the talent pool that takes the contracts as just a bunch of liars - Making it hard for the rest of us to get a contract that we are qualified for. Or the idea that you low-bid the contract, taking it away from a qualified software engineer only to come up on the forums and ask those same people to tell you how to do the job you just stole from them.

Totally unprofessional of you, on so many levels.

[evry1falls]

BobRodes, on 07 May 2012 - 08:36 PM, said:

evry1falls, on 07 May 2012 - 11:34 AM, said:

Why no-one ever rates me .... ?!

Don't take it personally. I've looked over your 20 posts, and in those you answer one question and ask 19. You don't get upvoted for asking questions, you get upvoted for answering them in helpful fashion. While I appreciate your upvoting people who help you, a lot of people don't do that. As you can see, I have posted over 1800 answers on here with no questions, and my rep votes are somewhat less than 300. Modi has posted over 14,000 answers and has a rep of about 3350. And you are asking for a rep of 1 or better for one answer? Have a look around.

I'm really sorry if my sense of humor offended you guys, i take it back, i really did not mean it the way you read it .. sorry

tlhIn`toq, on 08 May 2012 - 02:03 AM, said:

evry1falls, on 07 May 2012 - 07:40 AM, said:

I've took an assignment from some company and the requirements document said :

Quote

The program should use a three-tiered structures with presentation , business and persistence classes ??

I've no idea what is that mean.

Then why on Earth did you take the job? How did you figure the pay if you had no idea what the work involved? How would you know to bid 4 or 400 hours?

Accepting contracts that you KNOW you aren't qualified for is going to ruin your on-line reputation in a heart-beat. Do you want to make it even harder on yourself to find paying work?

You can do anything you like, it won't affect us but I would HIGHLY recommend you do not do something this silly again if you want to stay in this career field. Employers search those job sites... they search Google... They search Facebook... Hell they check your credit rating now days... If you ruin your reputation you'll have a hard time finding anything that doesn't involve the phrase "Do you want fries with that?"

That doesn't even begin to cover how unprofessional it is to tell an employer that you'll take the contract knowing you can't do the job. That employer probably has commitments and deadlines. You could have just cost someone thousands of dollars in late delivery charges. Possibly made someone in that company look REALLY bad and jeopardized their job.

Additionally that company may choose to not put work out for bid again because they see the talent pool that takes the contracts as just a bunch of liars - Making it hard for the rest of us to get a contract that we are qualified for. Or the idea that you low-bid the contract, taking it away from a qualified software engineer only to come up on the forums and ask those same people to tell you how to do the job you just stole from them.

Totally unprofessional of you, on so many levels.

Quote

The Three-tiered structure, business and presentation

in my job Requirements doc. was a plus not a must, and when i discussed it with my client, i was honest, i said ("Sorry, i won't do that, i have no idea what is it. It will take time to figure it out, and get it done on time as agreed."), he said ("It's ok, it is a plus not a must") ...

If there's an application that i know for sure i can get it done in time, but there's something or an idea or a tool in the programming language of the application which i'm sure i did not deal with it before , i just don't discuss that with my client, also that is not a reason that would stop me from taking the job .
Thank you all.

[BobRodes]

modi123_1, on 07 May 2012 - 03:35 PM, said:

Ah.. everyone in these parts seem to use MVC and three-tier interchangeably.

MVC was invented at Xerox in the late 70's and became the basis of Smalltalk architectures in the 80s. Three-tier and later n-tier architecture got its start in the early 90s, and became important probably because Microsoft was looking for a competing architecture to MVC (which Java was touting) and got behind it.

[evry1falls]

Could you show me examples of those different techs. ?!

[BobRodes]

I already did. See my post #2, particularly the last sentence. Forget about MVC right now. Go and do your homework.