Design of Inventory Application(C#) - c#-2.0

I would like to design a Inventory system. Some key features listed below.
Multi User
Multi Branch
Support Online and offline Invoicing
Multi Currency
Language requirements : -
C# 2.0
SQL2005 Server
I appreciate your valuable suggestions and ideas to design perfect Inventory system.
If you have any Database sample model to design such a system please don't hesitate to inform me.
Thanks.

You have some of your requirements listed here, but you do not have enough information to complete a design of an invoicing system, plus you have an unrealistic goal of a perfect inventory system - what is perfect for one person is imperfect for another; I'd settle for aiming for best of breed if I were you.
Do you have access to your customers? If you do, you need to sit down with them and find out what they want. A good way to do this is to model their working processes. Write down what steps they do from start to finish, and what influences their work (known as external actors or interfaces). This is a long process, but will end up with you being able to state exactly what is done, when, and in what order, plus the functional and non-functional constraints on the system.
Once you have this information, actually designing the physical system is relatively straightforward. Good luck.
[Big hint] The process I have described here makes heavy use of UML.[/Big hint]

Related

Difference between BPM and App. workflow?

I know there is a lot of talk about BPM these days and I am conscious that some may see it to be a craze rather than a fundamentally important piece of software.
As someone from what most would call 'The Business', I have been doing my best to learn about BPM to ensure we continue to make decisions that not only make sense to the business, but IT as well.
I have noticed while reading that mention is made to application workflow when sometimes discussing BPM. I hadn't given this much thought until recently.
Therefore, what is the difference? When would you use one and not the other?
BPM is about the process and improving it, which takes into account users and potentially more than one application,e.g. an ERP system may have more than one application to it, though there may be other uses of the term. Note that the process could be viewed without what applications or technologies are used.
Application workflow is how an application is used to go from a to b. Here it is a specific set of code that is used and what happens over the course of an application getting from a to b. In this case, the application is front and center rather than the process.
Does that provide an answer? Another way to think of it is that multiple application workflows can make up a system which is used in a process that can have BPM applied to it.
Late to the game, but workflow is to database as BPMS is to DBMS. (Convenient how the letters line up, huh?)
IOW, BPM(S) is traditionally meant to refer to a particular framework/application that allows you to manage business processes: defining them, storing them, versioning them, measuring them, etc. This is similar to how a DBMS manages databases.
Now, a workflow is a definition, much like a database is a definition. In the former case, it is a definition of operations/work (Fufill Order), steps thereof (Send Invoice) and rules/constraints on the work (If no stock, send notice). In the latter, similar case, it is a definition of data structure (CREATE TABLE) and constraints (InvoiceTotal must be > $0.00).
I think this is a potentially confusing subject, particular as some development environments use a type of process flow model to generate user facing applications (I'm thinking about Outsystems here, for example).
But, for me, the distinction is crystal clear. Application workflow, as people talk about it, refers to a user's path through an application, i.e. the pages they complete/visit, the data they enter, etc. on their way to completing a transaction of some sort. Application orkflow is a poor term for this though, I think application flow would be more meaningful.
BPM on other hand, is about modelling and executing a workflow process. By workflow, in this context, I mean a series of discrete steps (or tasks) that have to be completed (either programmatically or via human interaction) in a certain order to complete a process. These tasks can be implemented as individual application modules (each with their own "application workflow", see above). The job of the workflow engine is to make sure that these separate steps are assigned to the right people (of groups of people) in the right sequence, and that overall the process completes in an orderly way.
I don't think there's a clear answer to this at all. These are words, as opposed to theoretical concepts. If you add the word "checklist" into the mix - that just turns out to be a linear version of a process (but you can have conditionals in checklists - making them a workflow).
I am not sure how to help in reframing this question, but it's almost as if no answer can ever be possible. My own thoughts are at https://tallyfy.com/improving-efficiency-workflow-vs-business-process-management/

Functional Specifications

Whereever I have looked, the functional specifcations are some sort of documents with the requirements/proposed features represented and elaborated. I was recently in a position to make a standard template for our company for functional specifications.
The format I have settled for, tentatively, is an excel file with a quite a bit of automation.
The template plans to link top level requirements to lower level requirements in a hierarchy.
The lower level requirements can then be mapped to the technical aspects of the design, similar to the house of quality. The corelation is idetified as in the HOQ, but in addition, for each pair of requirements and technical aspect, a feasibility is estimated.
If any of the technical aspect for a requirement is marked as non-feasible, the requirement is flagged for reconsideration.
After all requirements are either flagged feasible or removed appropriately, each requirement-technical aspect pair is extracted and estimations sought for each of them in terms of time and budget.
The estimations help us in planning the project.
Can I have an informed opinion about this proposal? This seemed to me the best way to link requirements with technical aspects and then to project planning.
In my experience the functional specification was generally a use case document (with or without a corresponding diagram or diagrams). The spreadsheet sounds pretty cool, but functional requirements are generally for communicating with the business stakeholders with the goal of obtaining agreement and ultimately sign-off so the project's budget can be approved. Unless your spreadsheet can somehow format the requirements for print output, I'm a bit confused as to how you propose to share the contents for discussion and feedback.
My two cents...
Hope this helps,
Bill
You might want to add a mapping between low level requirements and tests (like "design test", not "unit test".
That way you can establish a broad functional testing coverage needed for that project.
"Can I have an informed opinion about this proposal?"
Who are your users for this spreadsheet?
What do your users do with this spreadsheet? What are their use cases for requirements gathering, planning and project approval?
If you are the user, then it's perfect for you.
If you are not the user, you need to meet with your users, determine the following:
What actions do the users of requirements take? Do they approve, reject, confirm, deny?
What decisions do they make?
What information do they need to make those decisions?
If your spreadsheet meets your users needs, then it's good.
Requirements are slippery things and must be reprioritized and reconsidered in very many ways. Too much spreadsheet automation can be a hinderance.
Mostly, folks need to be able to add an unlimited number of extra columns and sort them into innumerable organizations and reorgnizations.
You may need a supplemental to the spreadsheet for listing use cases and any user interface specs.

What is the most critical piece of code you have written and how did you approach it?

Put it another way: what code have you written that cannot fail. I'm interested in hearing from those who have worked on projects dealing with heart monitors, water testing, economic fundamentals, missile trajectories, or the O2 concentration on the space shuttle.
How did you prepare for writing this sort of code: methodologically, intellectually, and emotionally?
Edit
I've marked this wiki in case the rep issue is keeping people from replying. I thought there would be a good deal more perspective on this issue than there has been.
While I am not personally involved in what is described there, this article will hopefully contribute to the spirit of your question: They Write the Right Stuff.
I wrote a driver for a blood pressure measuring device for hospital use. If it "fails", the patient will not have his blood pressure checked at the scheduled time; if his blood pressure is abnormal, no alarm (in the larger system) will be triggered. Such an event could be clinically significant.
My approach was to thoroughly read the spec/documentation in a non-work environment (to avoid the temptation to start coding right away), then read it again at work. After that, I summarized the possible states and actions on paper and "flowcharted" an algorithm, and annotated all the potential real-world "bad events" (cables getting unplugged, batteries dying, etc). Finally, I wrote and rewrote the driver three times, each with different mechanisms (e.g. FSM), and compared their results. Each iteration helped me identify weaknesses I hadn't yet discovered. The third rewrite was the "official" result. I reviewed each iteration with my co-worker.
Emotional preparation consisted of convincing myself that should the unthinkable happen, at least I wasn't willfully negligent -- just incompetent (the old "I'm only human" excuse). ;-)
I have written computer interface to a MRI machine. It had no chance of hurting the end user as it was just record management, but it could potentially have given an incorrect diagnosis or omit important information.
Tests, lots and lots of tests.
Unit tests, mid and high level tests. Simulate all possible input combinations. Also a great deal of testing with the hardware itself. Testing must be done in a complete and methodical way. It should take a great deal more time to test than to write.
Error Reporting
All errors must be reported and be obvious. If it won't hurt the patent to do so, fail fast.
For something that is actively keeping a person alive things are even worse. It must never stop working. If it fails it needs to restart and keep trying. Redundant internals are also a must in case the hardware fails.
At the wrong company it can really a difficult kind of situation to work in. However, if things are going well, you are well funded and release pressure is not high, it can be a very rewarding space to work in.
Not really an answer, but:
I've got a friend who writes embedded control software for laser eye surgery machines. When he had laser eye surgery himself, he made sure to go to an ophthalmologist who used his company's system. I have great admiration for this guy. I can't think of a piece of software I've ever written whose level of quality was high enough that I'd trust my own eyesight to it.
Right now I'm working on some base code for a system that retrieves medical patient information from clinics and hospitals for a medical billing office. We're starting out with a smaller client and a long break-in period to ensure quality, but eventually this code needs to securely handle a large variety of report formats from a number of clients at different facilities.
It's not quite in the same scale as your examples, but a bad mistake could result in the wrong people being billed or the right person billed to a defunct address (screwing up credit reports) or open people up to identity theft, so it's still pretty critical. Oh yeah, and it could mean doctors don't get paid quite as quick. That's important, too, especially from a business perspective, but not in the same class as data protection and integrity.
I've heard crazy stories of the processes used to write code at NASA for the spaceshuttles. Every line of code has about 10-20 lines of documentation, along with tests, full revision history, etc. Every time a bug is found, not only is the code evaluated and repaired, but the entire procedure of writing code, the entire command chain, etc. is reviewed to answer the question: "What happened wrong in our process that allowed this bug to get included in the first place?"
While nothing quite so important as an MRI machine or a blood pressure monitor, I did get tapped to do a rewrite of Blackjack when I worked for an online gambling provider. Blackjack is by far the most popular online game, and millions of dollars was going to go through this software (and did).
I wrote the game engine separate from the server and the client, and used Test Driven Development to ensure that what I was assuming was coming through in the results. I also had a wrapper "server" that had console output that would allow me to play. This was actually only useful in that it mimicked the real server interface, since playing a text version of blackjack isn't very fun or easy ("You draw a 10. You now have a 10 and a 6, while the dealer has a 6 showing. [bsd] >")
The game is still being run on some sites out there, and to my knowledge, has never had any financial bugs after years of play.
My first "real" software job was writing a GUI app for planning stereotactic brain surgery. Testing, testing, testing... absolutely no formal methods, engineering-style thoughts, just younger programmers cranking it out. When they started talking about using the software to control a robotic arm with a laser, without any serious engineering methods in place, i got a bit worried, left for more officey lands.
I've created information system application for local government cultures and tourism department in Bali island which were installed in several tourism denstinations, providing extensive informations about the culture, maps, accomodations etc.
if it failed then probably tourists couldnt get the right informations they need most, cheat by brookers, or lost somewhere :)

"Multi-agent computing" in simple terms

I've encountered the term "multi-agent computing" as of late, and I don't quite get what it is. I've read a book about it, but that didn't answer the fundamental question of what an agent was.
Does someone out there have a pointer to some reference which is clear and concise and answers the question without a load of bullshit/marketing speak? I want to know if this is something I should familiarise myself, or whether it's some crap I can probably ignore, because I honestly can't tell.
In simple terms, multiagent research tries to design system composed of autonomous agents. That is, you have a bunch of robots/people/software-agents around, each of which can take its own actions but can only "see" stuff that is around him, how do get the system to behave as you want?
Example,
Given a bunch of robots with limited sensing capabilities, how do you get them to monitor a field for enemies? to find all the mines in a field?
Given a bunch of people, how do you get them to maximize the happiness of the least happy person? without taking away their freedom.
Given a group of people, how do you set up a meeting time(s) that maximizes their happiness? without revealing their private information?
Some of these questions might appear really easy to solve, but they are not.
Multiagent research mixes techniques from game theory, Economics, artificial intelligence, and sometimes even Biology in order to answer these questions.
If you want more details, I have a free textbook that I am working on called Fundamentals of Multiagent Systems.
A multi-agent system is a concept borrowed from AI. It's almost like a virtual world where you have agents that are able to observe, communicate, and react. To give an example, you might have a memory allocation agent that you have to ask for memory and it decides whether or not to give it to you. Or you might have an agent that monitors a web server and restarts it if it hangs. The main goal behind multiagent systems is to have a more Smalltalk-like communication system between different parts of the system in order to get everything to work together, as opposed to more top-down directives that come from a central program.
"Agents" are another abstraction in software design.
As a crude hierarchy;
Machine code, assembly, machine-independent languages, sub-routines, procedures, abstract data types, objects, and finally agents.
As interconnection and distribution become more important in computing, the need for systems that can co-operate and reach agreements with other systems (with different interests) becomes apparent; this is where agents come in. Acting independently agents represent your best interests in their environment.
Other examples of agents:
Space craft control, to make quick decisions when there's no time for craft-ground crew-craft messaging (eg NASA's Deep Space 1)
Air traffic control (Systems over-riding pilots; this is in place in most commercial flights, and has saved lives)
Multi-agent systems are related to;
Economics
Game theory
Logic
Philosophy
Social sciences
I don't think agents are something you should gloss over. There's 2 million hits on google scholar for "multi agent" and more on CiteSeer; it's a rapidly evolving branch of computer science.
There are several key aspects to multi-agent computing, distribution and independence are among them.
Multi-agents don't have to be on different machines, they could as #Kyle says, be multiple processes on a single chip or machine, but they act without explicit centralised direction. They might act in concert, so they have certain synchronisation rules - doing their jobs separately before coming together to compare results, for example.
Generally though the reasoning behind the segmentation into separate agents is to allow for differing priorities to guide each agent's actions and reactions. Perhaps using an economic model to divide up common resources or because the different functions are physically separated so don't need to interact tightly with each other.
<sweeping generalisation>
Is it something to ignore? Well it's not really anything in particular so it's a little like "can I ignore the concept of quicksort?" If you don't understand what quicksort is then you're not going to fail to be a developer because most of your life will be totally unaffected. If you have more understanding of different architectures and models, you'll have more knowledge to deploy in new and unpredictable places.
<sweeping generalisation>
Ten years ago, 'multi-agent systems' (MAS) was one of those phrases that appeared everywhere in the academic literature. These days it is less prevalent, but some of the ideas it represents are really useful in some places. But totally unnecessary in others. So I hope that's clear ;)
It is difficult to say what multi-agent computing is, because the definition of an agent is usually very soft surrounded by markting terms etc. I'll try to explain what is it and where it could be used based on the research of manufacturing systems, which is the area, I am familiar with.
One of the "unsolved" problems of modern manufacturing is scheduling. When the definition of the problem is static, an optimal solution can be found, but in reality, people don't come to work, manufacturing resources fail, computers fail etc. The demand is changing all the time, different products are required (i.e. mass customization of the product - one produced car has air conditioning, the next one doesn't, ...). This all leads to the conclusions that a) manufacturing is very complex, b) static approaches, like scheduling in advance for a week, don't work. So the idea is this: why wouldn't we have intelligent programs representing parts of the systems, working the way out of this mess on their own? These programs are called agents. They should communicate and negotiate amongst themselves and make sure the tasks are done in due time. By using agents we want to lower the complexity of the control system, make it more manageable, enable better human - machine interaction, make it more robust and less error prone and very importantly: make the control system decentralized.
In short: agents are just a concept, but they are a concept everyone can intuitively understand. Code still needs to be written, but it is written in a different way, one abstraction higher than OOP.
There was a time when it was hard to find good material on software agents, primarily because of the perception of marketing potential. The bloom on that rose has diminished so the signal to noise ratio on the Internet has improved vis-a-vie software agents.
Here is a good introduction to software agents on this blog post of an open source project for software agents. The term multi-agent systems just means a system where multiple software agents run and communicate and delegate sub tasks to each other.
According to Jennings and Wooldridge who are 2 of the top Mulit-agent researchers an agent is an object that is reactive to its environment, proactive and social. That is an agent is a piece of software that can react to its environment in real time in a way that is suitable to its own objeective. It is proactive, which means that it doesnt just always wait to be asked to perform a task, if it sees a chance to do something that it feels would be beneficial to its objectives it does it. And that it is social, ie that it can communicate with other Agents, doesnt nessecaily ever have to do any of these things in meeting its own objectives but it should be able to to do these if the situation arose. And thus a multi-agent system is just a collection of these in a distrubuted system that can all communicate and try to perform their own personal goals hat normally lead to an overall achievement of the system goal.
You can find a concentration of white papers concerning agents here.

How do I represent features v. tasks in FogBugz 6?

In FogBugz 6, how do I represent the concepts of a "feature" versus a "task"? As defined by Joel Spolsky, the owner of Fog Creek Software (which makes FogBugz), a feature is essentially a user-visible capability. To estimate the time to implement a feature, the developer should break the implementation into short tasks (2 days max) to ensure they think about each step.
FogBugz has only cases. I can't tell whether they're supposed to correspond to features or tasks. Some FogBugz documentation indicates that each case is a task, which is fine except there is no way to group all the tasks for a given feature together. This is especially odd given that, before FogBugz 6, Joel advocated using a spreadsheet with that grouped all the tasks for each feature. But his own software doesn't appear to meaningfully support that grouping.
I realize that the Joel article I reference includes a disclaimer pointing to a later article. However, the later article does not settle this issue, in fact it doesn't discuss features versus tasks at all, which is surprising given how well Joel advocates for those concepts in the first article.
For FogBugz 6.0 and earlier:
Make a case for each work item (task). FogBugz calls them "Features," only to distinguish them from bugs, but you do want one case for each task.
The best way to group a bunch of tasks is to make a Release (Fix-For) and assign all of the tasks to that release.
Responding to AviD's comment/question to Joel:
So, if you have 10 new features coming
in the next version, with each feature
needing 5 tasks to implement, you
recommend creating 10 releases? And
how do I define that these are the
features/"releases" that are to be
included in the upcoming release?
Here is how we dealt with this specific problem in our development process:
First, we made a regular release schedule: monthly internal releases and quarterly external releases. This schedule never changes but task assignment / feature completion does. This is hugely important in terms of simplifying our inter-human communication: don't try to argue with the calendar.
Major features ("10 new features" in your example) are turned into cases (e.g., case 101 to case 110).
Each task that is a sub-component of a major feature also gets created as a sub-case with a description of what makes this chunk of work an important part of the larger picture. Previously, in Fogbugz 6, we used the "See also" feature by allowing it to search the text for us ("This is a sub-component of case 101" for example). This was effectively the same thing but less aesthetic.
Now that we've broken down the work to its finest level of usefulness, we bring the actual developers into the discussion. Each task and major feature is individually assigned to a particular developer.
The developer determines when they can get their assigned work done by picking the appropriate internal release date that they think they can commit to.
At this point, we have a rough sketch of what will get done for each release. Further refinements continue as the working people actually estimate the hours that they'll need to do the work, enabling evidence-based scheduling, etc.
For AviD's question, though, he would have the release-assignment problem solved by step 5 above.
However, I think point 6 is the most interesting as that's where you really get a solid schedule. For example, if developers are having trouble estimating a larger task, they break it down into sub-cases even further. Notice how my assessment of "finest level of usefulness" can differ (perhaps greatly) from the person who really needs to get the work done.
This is also a time when a developer can reach out to someone else and say "I can do most of this but it would really help if person X could help me with this little piece Y." This is actually where I get most of my development tasking: I personally sit in multiple places during this process, from large-scale planning meetings to little fiddly tasks that no-one else has time to do.
PS: Making it a personal goal to get this answer rated higher than Joel's.... ;-)
PPS: My original response is now overcome by events since Fogbugz 7 has lovely sub-tasks. Program managers love those reports.
You may have better luck asking your questions in the FogBugz Discussion Forum
We use a combination of projects in order to accomplish your grouping goals. We also commonly setup a project "parking" Wiki where links to development cases, technical documentation, systems requirements, user documentation, external links to resources etc. can all be placed. It provides a good "one-stop-shop" for everything related to that project.
As part of that Wiki, we would then setup two specific projects. One in relation to the large overall goals/outlines similar to what might correspond to your Project Management charts/whatnot. One in relation to the development tasks of each feature as they are broken down into the smaller and more manageable chunks. You can then, as was mentioned use case linking to both reference the "master" cases in the other project as well as reference the project Wiki itself so that you can quickly and easily get back to all of your project related information which is conveniently in one spot.
You can accomplish a pile of different organizational structures using FogBugz, you just have to approach things a little differently sometimes in order to hit each and every situation.
Hope that helps.
haha, that article has a disclaimer, but I understand what you are saying.
We use Fogbugz and the only 'Feature' that I am aware of is under category and I don't think you can associated it with sub-tasks.
You can type in 'Case N' is the feature for this task if you just wanted to reference it in the case text.
That kind of stuff sound like is lies more in the project management domain instead of software used to track bugs.
thats a good question, i have asked that myself, too..
we currently test-drive fogbugz for 45 days in a group of 5 developers, and we currently create a "release" for major features. in fact we do not release it, but multiple releases together when something is ready.
there should definately be some sort of advanced task grouping in fogbugz.

Resources