I'm an OSX beginner. Where is the best place to store an NSMutableArray of objects. the objects need to be presented to the user for updating, deleting etc. I've already written the code to manage and present the data to the user. i just need to now start saving the data. i don't envisage the array containing more than 50 objects.
i'm not sure where to persist the data. should i use a os file or NSUserDefaults. what does osx etiquette say?
thanks
Since you mention that the user will need to update and delete the data, Core Data is a very good option.
In addition to the benefits of the framework itself, Core Data integrates well with the OS X tool chain. The model design tools allow you to create your schema graphically, quickly and easily. You can use templates in the Instruments application to measure Core Data’s performance, and to debug various problems. On OS X desktop, Core Data also integrates with Interface Builder to allow you to create user interfaces from your model. These aspects help to further shorten your application design, implementation, and debugging cycles.
You can read more about the key features in the documentation to be sure that's what you're looking for.
I don't have a specific question here but I'm more looking for some guidance regarding a new software project I'm starting at work.
Here is a description of the project:
I am refactoring windows software that was written in Visual Basic 6 and uses MS SQL Server for a database. The code is tightly coupled with SQL queries and references old active X controls.
The software can run in a standalone mode where its only running one instance on one computer or in a distributed mode where it runs on several machines simultaneously all connected to a shared data source.
The users of the software need use of a wide range of USB devices that are integrated with the software on the client side. (I'm assuming this means the new version of the software needs to be a desktop application and can not be a browser based web application.)
The new version of the software is going to be updated to use new technologies in an effort to modernize the code and improve performance.
I would like the architecture of the new software be both logical 3-tiers and to use design patterns if appropriate. Although I am new to design patterns it seem like there is an opportunity to use the abstract factory, observer, and singleton patterns together in the new version of the software.
In a very generic explanation the software has an "employee" database table that stores information about employees. The client side has a grid view that allows the user to view the employee information stored in the database and to make modifications to the data through the grid view. Data can be added to the employee database by the client using forms that have text fields and drop down menus. Employee related data can also be captured by USB devices on the client side and then that data can be added to the employee database as well.
In terms of how this relates to architecture I'm guessing there could be an observable singleton employee object that is observed by data display objects like a grid view object and that these data display objects are created by an abstract factory method. (Does that make sense?)
The new software will be written in Visual Basic using Visual Studio 2010. Aside from that none of the other technologies have been decided upon.
I think we will use windows forms opposed to the windows presentation foundation although I'm not sure as there might be some image handling functionality that we want that is better done with WPF.
From what I've read I like the Entity Framework and Linq but I'm not sure how that works in conjunction with the business logic layer with the design patterns I mentioned above.
Also, I'm trying to understand if we could use the windows communication foundation and web services. This makes sense when the software is running in distributed mode but not much sense in the standalone single machine deployment. Adding web services and using IIS might be overkill for what we are trying to accomplish. I don't know.
So this is what I'm working on and what I've been reading about and researching. I would greatly appreciate your thoughts on this and any guidance you can provide.
Thanks!
Aside from the fact that you will learn a lot during the development process I can give you the following recommendations:
Use Stored Procedures in the database for database access. This will prevent concurrency problems and also allows for transactions. This means if something goes wrong (users computer crashes etc) then no data nor data integrity is lost
Treat the windows forms as simply 'interfaces' between the user and the database. Hence they shouldn't contain anything that keeps track of data (let the database do that) and they're only a means of gathering and showing data
I had a very similar experience.
I tried importing a VB6 database project that ran as a standalone app into VB 2005, and the code was very ugly.
One book that I found very helpful with doing three-tier DB applications using VB.NET (VB 2005, actually) was ADO.NET 2.0 with VB 2005 published by Murach. Got me up to speed very quickly, and it gave direct examples of writing three-tier DB applications (business layer, presentation layer, and DB access layer).
Can't remember for sure if there's a newer version of the book, but I was impressed with the layout of that one. It also deals with web apps.
Beyond that, I did some code generation to streamline hacking out the Object classes and the DB access classes for my project.
I believe this project is really going to have you learn and gain a lot of experience.
Like eddy556 said, use the forms only as interfaces. It works better that way.
Plus, if you have any problems, don't hesitate to ask. That's what we the StackOveflow team are here for anyway.
Good Luck.
I have the following dilema: My clients (mom-n-pop pawnshops) have been using my mgmt. system, developed with ISQL, for over 20 years. Throughout these two decades, I have customized the app to each clients desire, or when changes in Laws/Regulations have required it. Most clients are single-user sites. Some have multiple stores, but have never wanted a distributed db, don't trust the reliability or security of the internet or any other type of networking. So, they all use Standard Engines. I've been able to work around some SE limitations and done some clever tricks with ISQL and SE, but sooner or later, new laws may require images of pawnshop customers, merchandise, electronic transmision, etc. and then it will be time to upgrade to IDS, re-write the app in 4GL or change to another RDBMS. The logical and easiest route would be IDS/4GL, however, when I mentioned Linux or Unix-like platforms to my clients, they reacted negatively and demanded a Windows platform, so the easiest solution could be 4Js, Querix, etc.?.. or Access, Visual FoxPro or ???.. anyone have suggestions?
This whole issue probably comes down to a couple of issues that you'll have to deal with.
The first thing is what application programming and development language Are you willing to learn and work with?
The other thing is what kind of Internet capabilities to you want?
So for example while looking at a report do you want to be able to click on a button and have the report converted to a PDF document, and then launch the e-mail client with that PDF attached?
What about after they enter all the information data into the system, perhaps each store would like their own miniature web site in which people in town could go there to check what they've have place of having to phone up the store and ask if they have a $3 used lighter (the labor of phone and checking for these cheap items is MORE than the cost of selling the item – so web really great for this type of scenario).
The other issue is what kind of interface do you want? I assume you currently have some type of green screen or text based interface? Or perhaps over the years you did convert over to a GUI (graphical user interface).
If still green screen (text based) you now you have to sit down and give a considerable amount of effort and time into the layout and how you of screens will work with a graphical based system. I can remember when going from green screens to color, all of a sudden now the choices and effort of having to choose correct colors and layouts for that screen actually increased the workload by quite a bit. And then I went from color test screens to that of a graphical interface, then again all of a sudden now we're presented with a large number of new controls, colors, and in addition to that we have large choices in terms of different fonts and sizes.
And then now with the web, not only do you deal at different kinds a button styles (round, oval, shading, shadows, glow effects), but in addition to all those hover effects and shading effects etc, you now have to get down to some pretty serious issues in terms of what kind of colors (theme) your software will adopt for the whole web site.
This really comes down to how much learning and time you are willing to invest into new tools and how much software you can and will produce for given amount of time and effort.
I quite partial to RAD tools when you get down into the smaller business marketplace. Most of the smaller businesses can not afford rates for a .net developer (it not so much the rate, as the time to build an application). So, using ms-access is a good choice in the smaller business market place. Access is still a good 3 to 5 times many of the other tools in the marketplace. So quote by .net developer to develop something might be 12,000 bucks, and the same thing in Access might be $3000. I mean that small business can not afford to pay you to write unit testing code. This type of extra cost is just not going to happen on the smaller scale projects.
The other big issue you have to deal is what kind of report writing system are you going to build into the system? This is another reason why I like for the smaller business applications is access is because the report writer is really fantastic. Access reports have a whole bunch of abilities to bake connections in from forms and queries and pass filters and parameters into those reports. And, often the forms and queries that you spend time building already can talk to reports with parameters and pass values in a way that again really reduces the workload (development costs).
I think the number one issue that you'll have to address here however is what you're going to do for your web based strategy? You absolutely have to have one. Even if you build the front end part in access, you might still want to use a free edition of SQL server for the back end part. There are several reasons for this, but one reason is then it makes it easy to connect multiple stores up over the Internet.
Another advantage of putting your data in some type of server based system, is now you can set up some type of web server for all the stores to use, and build a tiny little customize system that allows each store to have their products and listings online (but, they use YOUR web server, or one that you paying $15 per month to host all of those customers). This web part could be an optional component that maybe perhaps all customers don't necessarily want. It would work off of the data they have to enter into the system anyway.
One great advantage of adopting these web based systems is not only does it allow these stores to serve their customers far better, but it also opens up the doors for you to convert your software into a monthly fee based system, or at least some part of it such as the optional web hosting part you offer.
When I converted so my longer time applications from green screen mainframe type software into windows desktop based applications it opened up large markets for me. With remote desktop, downloading software, issuing updates from a web site, then these new software systems make all of these nuts and bolts part of delivering software very easy now and especially so for supporting customers in different cities that you've never met face to face.
So, if you talking still primarily single user and one location, Access will reduce your development costs by a lot. It really depends on how complex and rich of an application you are talking about. If the size and scope of the project is beyond one developer, then you talking more about developer scaling (source code control, object development methodology, unit testing, cost and time of setting up a server based database system like SQL server etc). So they're certainly tipping point here when you go beyond that tipping point of cost time in complex city, then I actually don't recommend access. So this all comes down to the right horse for the right course.
Perhaps that the end of the day, it really comes down to what application development system are you willing to invest the time to learn?
Look at Aubit4GL - that is, I believe, available (or can be compiled on) Windows.
Yes, IDS is verging on overkill for a single-user system, but if SE doesn't provide all the features you need, or anticipate needing in the near future, it is a perfectly sensible choice. However, with a modicum of care, it can be set up to be (essentially) completely invisible to the user. And for a non-stressful application like this, the configuration is not complicated. You, as the supplier, would need to be fairly savvy about it. But there are features like silent install such that you could have your own installer run the IDS installer to get the software onto the customer's machine without extra ado. The total size of the system would go up - IDS is a lot bigger on disk than SE is (but you get a lot more functionality). There are also mechanisms to strip out the bigger chunks of code that you won't be using - in all probability. For example, you'd probably use ON-Tape for the backups; you would therefore omit ON-Bar and ISM from what you ship to customers.
IDS is used in embedded systems where there are no users and no managers working with the system. The hardware sits in the cupboard (closet) and works, communicating over the network.
It's good to see folks still getting value out of "old school" Informix Tools. I was never adept at Perform, but the ACE report writer always suited me. We skipped Perform and went straight for FourGen, and I lament that I've never been as productive as I was with FourGen. It had it own kind of elegance from its code generators to it funky, but actually quit powerful, stand alone menu system.
I appreciate the modern UI dynamics, but, damn, is it hard to write applications today. Not just tools, but simply industry requirements et al (such as you may be experiencing in your domain). And the Web is just flat out murder.
I guess part of it is that since most "green screen" apps look the same, it's hard to make one that looks bad! With GUIs and the Web etc., you can't simply get away with a good field order and the labels lining up.
But, alas, such as it is, that is what we have.
I have not used it in, what now, 15 years, but you may also want to look at Alpha 5. It was a pretty powerful, but not overly complicated, database development package, and (apparently) still going strong.
I wouldn't be too afraid of IDS. It runs pretty simply. Out of the box with zero or little tweaking, the DB works and is efficient, and it used to be pretty trivial to install. It was no SE, in that SE's access was tied to the application (using a library) vs an independent server that is IDS. But, operationally, it's really straightforward -- especially for an app like what you're talking about. I appreciate that it might be overkill, but even today, the resource requirements won't necessarily be insane. There's a lot of functionality, of course, and flexibility that you won't use. But frankly, beyond "flat file" DBase style databases, pretty much ALL of the server based SQL databases are very powerful and capable and potentially complicated. But they don't have to be. They can still be used "simply" and easily (well, save for Oracle -- Oracle can't do anything "simply").
As far as exploring other solutions, don't be too afraid of the "OOP" stuff, as most applications, while they leverage OOP libraries, aren't really OOP themselves (they can be, they just typically aren't, they simply don't need to be). The biggest issue with many of the OOPs systems, is they're simply to finely structured. Dealing with events at far too low of a level. While many programs need to access to that fine level of control, most applications, particularly the ones much like yours, do not. So, the extra flexibility simply gets in the way or creates more boiler plate.
That said, you shouldn't be frightened away from them per se, citing lacking of expertise. They can be picked up reasonably quickly. But I would certainly exhaust the more specialized tools (like Alpha 5, or Access, etc.) first to see if they don't offer what you want.
In terms of Visual FoxPro, was and remains a peerless tool (despite flak from people who know little about it). It has a fast, native database engine, built-in SQL and powerful report designer and so on. But you also have to consider that Microsoft support will be dropped for it in 2014, there will never be a 64-bit version, and so on. And the file locking method it uses will be increasingly flaky on future versions of Windows IMO.
I'm a bit confused regarding the document architecture. Lets look at MSN for Mac - what would the document be in that application? The contact list? The text we insert to talk to other people?
When the need comes to save or read data into the application, what type of data should it read? Contact lists or chat logs?
Update:
Pushing this a bit forward, what is a document? A file type that the application is prepared to open?
Maybe MSN for mac isn't a document-architecture application. Not every program needs to use the same system.
In general, a 'document' is just what you say; the data that makes up your application's files. It can refer to documents on disk - which have a particular filetype, or runtime documents, which are a collection of interrelated model objects in your application.
Your application might support saving/loading documents of various different on-disk filetypes, but they could all be represented with the same model objects at runtime.
MSN clients and other chat applications create and view logfiles. They can't edit them, as far as I know, but that's a feature - they're logfiles after all. There are easier ways to create such logfiles, but there is a nice pseudorandom quality to the way these applications do it which some people prefer. Sort of like SO but different.
I have a contact manager program that I'd like to design for multiple network marketing companies. My desired structure would include a core program which covers basic contact management functions. After that one could purchase a module for their specific network marketing company. This module would contain a variety of controls that the original program would need to be able to manipulate. Here is an example of what it would have to have:
A group box containing buttons that link to a genealogy view, and the option to import one's donwnline from the back office provided by a company.
A panel which is displayed on the contact page allowing the user to input business information or which will be filled by importing a downline from the back office: ie business ID, qualification level, sponsor information etc.
a panel displayed when one searches for contacts on the contact list page which allows the user to sort based on information such as when they joined, what their business id is and so forth.
a panel which is displayed in a personal business overview page which presents to an individual how many people in their downline are at each qualification level and develop a mailing list for individuals of a certain qualification level.
I have the code developed to perform all these functions, I just wanted to give you an example of what needed to be done. I'm thinking that what I'm trying to create is a library that one can download and the program will recognize, but I'm not really sure where to go. What I'm really trying to do is figure out what kind of file I can make that will contain all this code and the GUI information that the program will recognize.
Any ideas?
With thanks,
John
Well, my solution would be to do it not in a plug-in style, but what I like to think of as a "custom update" style with database integration. The way you would do it is do a specific update for a company by making a .msi installer or something similar for the "new" (or old) version of the program for them. This could do anything from installing the original, clean version of the program, or installing another version with the code changes made specifically for them. Project-wise, it would be best to store these changes in separate folders, as in a SVN or CVS repository.
Now, take this with a grain of salt, since this may be a lot of work, depending on how many "updates" you are planning on doing. Of course, this could be what you're looking for because, once you have an update, you don't have to reprogram it to distribute it to another company. You just branch it and make any necessary changes to the already existing code.
It appears that the last comment on those forums proved to be the most helpful. I ended up with a design where the main program is the host and the interface. I've been taking a while to absorb how the assembly code operates in the hopes of learning more about it...that's how I learn really...mess and tinker with things, read descriptions and try using in different scenarios. This is a little challenging to debug but I'm growing confident that I'm heading in the right direction.