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I found around 8 Strenghts and flaws of using APEX over another program(http://en.wikipedia.org/wiki/Oracle_Application_Express), but i am not sure i quite understand WHEN to use it.
From what i understand, if you want a fast and easy-to-use development tool related to Oracle, Apex is your first choice. While if you need a complex solution, APEX won't fit.
I would like to know you guys opinion on this. In my case, i need to know if i should recommand this product or not for a raquetball club. Since it is not a big company, i believe HTML DB would be the best choice because we want as less manipulations as possible once it's implemented. We also don't want the owner of the club to pay a lot of money to get somoeone who can develop updates.
Apex is free, and an oracle XE database is free too. Apex is rapid development.
But what you're asking depends on so much more.
From what i understand, if you want a fast and easy-to-use development
tool related to Oracle, Apex is your first choice.
Is an oracle database already being used?
Easy to use dev tool: yes, sure. But as with anything, it depends on whether you have some experience with it, what the specs and expectations are, ...
While if you need a complex solution, APEX won't fit.
Well,... Would a complex solution be so much less complex in another environment? Just how complex are we thinking? In my opinion, you can go pretty far in apex and adapt it to your needs. it might involve creating templates and plugins to set up a framework, but it is doable. An example would be apex projects whom have been completely integrated with ExtJS. Apex is not the answer to everything too, but it's good. If you'd stay within the Oracle stack for more involved/complex, i'd say the next thing is ADF. Personally, i'm not convinced by that one though. It also has its pros and cons (such as: requiring java knowledge. pro for some, con for others...)
In my case, i need to know if i should recommand this product or not for a raquetball club. Since it is not a big company, i believe HTML DB would be the best choice because we want as less manipulations as possible once it's implemented.
How large is this club? How intense will the website be used?
Is there a DB already? Is it Oracle?
Who has DBA knowledge (even basic)?
Who will develop?
If your specs are up to spec, then much fiddling shouldn't be necessary after the launch.
We also don't want the owner of the club to pay a lot of money to get somoeone who can develop updates
Who will host the server? Who will run it? Who will administrate it? Do you plan to go cloud-based?
I'd almost ventured to suggest PHP may be a good alternative if this is a small project. Those developers may be easier to find and less expensive than an apex/oracle developer. But then again, if you're planning to outsource it may be less of an issue. If your oracle instance would be in the cloud somewhere, you'd even be pretty safe i'd believe...
Really, what options are you trying to compare? You're asking about apex, do you have any experience with it?
Honestly, your question is not so much a question as it is an opener to a discussion. Each technology and database will have its pro's and cons, fans and dislikers.
Personally, i really like apex. It has a lot going for it, especially when you're already invested in the Oracle stack. And it is still growing, getting good support, and great releases with lots of new features.
I can't really say how it must be set up a (reliable) service from the ground up: server and database, doesn't matter how small, you'll need some understanding and knowledge for that. If you just wing it and cross your fingers, you'll burn them somewhere down the line. Same with development. But as far as i'm concerned that goes for any other tech. Unless you outsource those aspects of course.
Etc etc. There is much and more to be discussed this way.
I put a downvote there for these reasons: there is much to be discussed, it isn't really much of a question which has a conclusive answer. And it maybe only could fetch a conclusive answer if you put more specifications up there and get people of the concurrent platforms to respond.
Edit
I'd like to react on Daniel's post.
First I have to say that I am originally a PHP-Developer, and I really like this language and environment. Nevertheless I decided to do an internship this summer, where I am currently working with APEX. Together with another intern I am developing a bigger application, and I hope to give you some useful input. This only covers the development of the application, as I am not really involved in things like database administration and so on (although I have to say that a PHP Webspace with a MySQL Database also isn't to hard to administrate, especially if there are not too many users).
I'm a developer too, and i don't do server and database administration (corporate environment). Not that i haven't dabbled a bit here and there in my spare time, but i digress.
But my experience is that it gets very, very hard to solve tasks which are out of this range. That doesn't mean that you can't get multiple tables in one reports, some joining of tables is also not a big problem, and can be easily achieved. But if your application needs even more than this I cannot recommend APEX, so I totally agree with your rule, that complex applications should be created in another way.
So speaking as a PHP developer, would you even recommend PHP to achieve this? Would it be less or just as complex?
I'd also argue about complexity. I've worked on some large forms, which for me by now means there are more than your average amount of items, some dynamic actions, validations, maybe some custom process(es). I've not encountered extremely complex situations and honestly i'd question who created those expectations. Thinking outside the box may be a virtue at times, but that doesn't mean the box is always bad. Complex mechanisms or pages can maybe be broken down into more easily accomplishable parts. An example would be using modal pages to break it up.
I also think that the slogan with the limited programming experience is only partial true. It is only true if you have only easy applications, as you have already said. I personally also can't stand the mixing between an IDE and "easy to use"-forms.
I agree about limited programming experience: you'll only create the most basic forms and reports, and having almost no experience i'd think you'd shy away from even option pages in fear of breaking something. Same thing goes for even basic db and server administration: i wouldn't like to rely on such a person when there is no experienced backup (but a very small project as is apperently being described might be acceptable).
I too am only invested in the programming side.
It's also not very easy to create new templates and other things, at least in my opinion it would be much easier with other frameworks.
I'd say that the templates make things very flexible and are certainly not hard to use
And maybe even the worst thing: I think that this application is quite buggy. I don't know how many times simple deleting and new creation of a process/page/validation or whatever solved a problem, where you are simply not thinking of this solution.
Wow. I strongly disagree with this. I've maybe encountered one such thing over the course of a year and tons of forms. Not that i haven't heard of some problems on the OTN forums, but usually they had to do with upgrades.
Summary: I would only use APEX if you have application which REALLY fits it. That means just reports and forms, everything which is more results in pain debugging sessions (as this is also not easy in this environment...) and bad maintenance.
It is too bad that there are not that many large, public sites which use apex out there. As far as i'm aware, there are and have been large project involving apex, but those usually are in a corporate environment and thus are never shown off (can't be). I personally believe apex can be pushed a lot further than the basic forms+reports you mention (and i mean basic, because things will usually come down to forms+reports in this context).
Debugging does not have to be a pain though. If you provide enough debug messages and comments in your own code, that will help a great deal. Debugging the page, javascript console, and if needs be an autonomous error logging procedure to be used in your plsql packages,... I'd say there is plenty to help out (and if you're driven to this, you are working on some more complex material, and i assume that you have the knowledge to actually deal with the complexity you've set up).
And interesting point you raise lastly is maintenance though. I'd say a point on which apex should improve a lot is versioning, out of the box. Exports need to be improved so they can be broken up a lot easier.
Wow, look at that wall of text... I could've guessed this would turn out into a discussion.
First I have to say that I am originally a PHP-Developer, and I really like this language and environment. Nevertheless I decided to do an internship this summer, where I am currently working with APEX. Together with another intern I am developing a bigger application, and I hope to give you some useful input. This only covers the development of the application, as I am not really involved in things like database administration and so on (although I have to say that a PHP Webspace with a MySQL Database also isn't to hard to administrate, especially if there are not too many users).
To start we created a few applications, just to get a feeling. Afterwards we started with the easy parts of the application. APEX is really great if you only have to build some reports and forms to edit the entries of the database. It's very fast to create these things with the integrated wizards.
But my experience is that it gets very, very hard to solve tasks which are out of this range. That doesn't mean that you can't get multiple tables in one reports, some joining of tables is also not a big problem, and can be easily achieved. But if your application needs even more than this I cannot recommend APEX, so I totally agree with your rule, that complex applications should be created in another way.
I also think that the slogan with the limited programming experience is only partial true. It is only true if you have only easy applications, as you have already said. I personally also can't stand the mixing between an IDE and "easy to use"-forms. It's also not very easy to create new templates and other things, at least in my opinion it would be much easier with other frameworks.
And maybe even the worst thing: I think that this application is quite buggy. I don't know how many times simple deleting and new creation of a process/page/validation or whatever solved a problem, where you are simply not thinking of this solution.
Summary: I would only use APEX if you have application which REALLY fits it. That means just reports and forms, everything which is more results in pain debugging sessions (as this is also not easy in this environment...) and bad maintenance.
I am posting here as a guest--hopefully, I will create an account. I used O-HTML-DB from its early releases. We built pretty fine apps. I last used it in 2004, having moved to non-development roles.
Since 2007 though, I decided to revisit the tool and found out about APEX. I have since had my own test apps. I disagree with most of what the intern says.
If you have a limited objective (your business need and associated requirements), then your use of APEX will be limited. This is a very robust application, with sophisticated security features (I have been in InfoSec/Cyber since 2009.
Yes, you are correct than claims about APEX not requiring a solid development background are not accurate. You need to have a sound grasp of SQL/PL/SQL, JavaScript. But you c an also take great advantage of OTN, where developers generously share their know-how. When I started with O-HTML-DB, I had never built a DA in a business environment before. I had theoretical SQL skills. I was a Web Developer with a grasp of JavaScrip, training in Java from Learning Tree International (in addition to academics). But I and my colleague (we were two developers) learned a great deal from OTN. We built three Web apps, one of which supported over 6,000 users--just O-HTML-DB!
APEX has taken O-HTML-DB to new dimensions. You do not need to hard-code validations like we did with O-HTML-DB. Of course, you can modify, which requires a sound grasp of SQL/PL/SQL.
Maybe templating is somewhat confusing to many developers, understandably. But as you continue to "play" with APEX, I am sure you'll like it. It can do nearly anything. Only your limited vision will restrict it.
Erick
Related
I'm asking the question after reading this article
http://stevehanov.ca/blog/index.php?id=95
Also isn't it a penalty to use cgi instead of fastcgi ?
Update: why some people do pretend like in answer "that you get 20-30% performance improvement" ? Is it pure guess or is this number coming from solid benchmark ? I have looked at HipHop performance is more in the scale of 10 times.
I've done webdev in a few languages and frameworks, including python, php, and perl. I host them myself and my biggest sites get around 20k hits a day.
Any language and framework that has reasonable speed can be scaled up to take 20k hits a day just by throwing resources at it. Some take more resources than others. (Plone, Joomla. I'm looking at you).
My Witty sites (none in production yet) take a lot more (from memory around 5000% more) pounding (using seige) than for example my python sites. Ie. When I hit them as hard as I can with seige, the witty sites serve a lot more pages per second.
I know it's not a true general test though.
Other speed advantages that witty gives you:
Multi threading
If you deploy with the built in websrever (behind ha-proxy for example) and have your app be multi-threaded .. it'll load a lot less memory than say a perl or php app.
Generally with php and perl apps, you'll have Apache fire up a process for each incoming connection, and each process loads the whole php interpreter, all the code and variables and objects and what not. With heavy frameworks like Joomla and Wordpress (depending on the number of plugins), each process can get pretyy humungous on memory consumption.
With the Wt app, each session loads a WApplication instance (a C++ object) and it's whole tree of widgets and stuff. But the memory the code uses stays the same, no matter how many connections.
The inbuilt Web2.0 ness
Generally with traditional apps, they're still built around the old 'http request comes in' .. 'we serve a page' .. 'done' style of things. I know they are adding more and more AJAXy kind of thigns all the time.
With Wt, it defaults to using WebSockets where possible, to only update the part of the page that needs updating. It falls back to standard AJAX, then if that's not supported http requests. With the AJAX and WebSockets enabled clients, the same WApplication C++ object is continually used .. so no speed is lost in setting up a new session and all that.
In response to the 'C++ is too hard for webdev'
C++ does have a bit of a learning curve. In the mid nineties we did websites in Java j2ee. That was considered commercially viable back then, and was a super duper pain to develop in, but it did have a good advantage of encouraging good documentation and coding practices.
With scripting websites, it's easy to take shortcuts and not realize they're there. For example one 8 year old perl site I worked on had some code duplicated and nobody noticed. Each time it showed a list of products, it was running the same SQL query twice.
With a C++ site, I think it'd have less chance because, in the perl site, there wasn't that much programming structure (like functions), it was just perl and embedded html. In C++ you'd likely have methods with names and end up with a name clash.
Types
One time, there was a method that took an int identifier, later on we changed it to a uuid string. The Python code was great, we didn't think we needed to change it; it ran fine. However there was little line buried deep down that had a different effect when you passed it a string. Very hard to track down bug, corrupted the database. (Luckily only on dev and test machines).
C++ would have certainly complained a lot, and forced us to re-write the functions involved and not be lazy buggers.
With C++ and Java, the compiler errors and warns a lot of those sorts of mistakes for you.
I find unit testing is generally not as completely necessary with C++ apps (don't shoot me), compared to scripting language apps. This is due to the language enforcing a lot of stuff that you'd normally put in a unit test for say a python app.
Summary
From my experience so far .. Wt does take longer to develop stuff in than existing frameworks .. mainly because the existing frameworks have a lot more out of the box stuff there. However it is easier to make extremely customized apps in Wt than say Wordpress imho.
From people I've spoken with who've moved from PHP to Wt (a C++ web framework) reported significant improvements. From the small applications I've created using Wt to learn it, I've seen it run faster than the same PHP type applications I created. Take the information for what you will, but I'm sold.
This reminds me how 20-30 years ago people were putting Assembly vs C, and then 10-20 years ago C vs C++. Of course C++ will be faster than PHP/Rails but it'll take 5x more effort to build maintainable and scalable application.
The point is that you get 20-30% performance improvement while sacrificing your development resources. Would you rather have you app work 30% faster or have 1/2 of the features implemented?
Most web applications are network-bound instead of processor-bound. Writing your application in C++ instead of a higher-level language doesn't make much sense unless you're doing really heavy computation. Also, writing correct C++ programs is difficult. It will take longer to write the application and it is more likely that the program will fail in spectacular ways due to misused pointers, memory errors, undefined behavior, etc. In general, I would say it is not worth it.
Whenever you eliminate a layer of interpretive or OS abstraction, you are bound to get some performance gain. That being said, the language or technology itself does not automatically mean all your problems are solved. I've fixed C++ code that took many hours to process a relatively simple set of records. The problem was in the implementation, and the fix was not related to the language's features or limitations.
Assuming things are all implemented correctly, you're sure to get better performance. The problem will be in finding the bugs. One of the problems with C++ is that many developers are currently "trained" or accustomed to having a lot of details related to memory management behind objects. This eliminates the need to consider things like, "What can happen if I pass this pointer around to several threads?" Sometimes it works well, but not always. You still have some subtleties of the language that you need to consider regardless of how the objects hide the nasty details.
In my experience, you'll need several seasoned C++ developers watching over the code to be able to keep the bugs and memory leaks from getting out of hand.
I'm certainly not sold on this. If you want a performance gain over PHP why not use a Java (or better yet Scala) framework? These are much better for web development, have nice, relatively easy to use frameworks and avoid a lot of the headaches of C++. I've always seen one of the main pluses of web-development (and most modern non-scientific/high performance applications) as being able to avoid the headaches that come along with C/C++ development.
As a hobby project I am trying to create a ROM (Diku-Merc based) derivative. (Now defunct) I would appreciate it if anybody has done something similar and has some useful resources to share or tips to offer. I'm finding that a lot the resources such as mailing lists are no longer active and many links are dead.
I've picked ROM because that is what I am familiar as a player, but the source is more complicated than anything I have come across and I wouldn't mind picking a code base that was easier to understand. Any recommendations before I dive in in earnest would also be appreciated.
As for mudding communities in general I don't know of much beyond the mud connector because I've always been in more of a user/player role than developer. A forgiving and active place where I can get answers to my questions is what I value most.
After extensive research I've decided to go with a tba code base. I may elaborate later but very broadly
Coding experience is more important than experience as a player and this has convinced me to abandon my roots. I wanted a well documented, reasonably modern, managable code base undergoing active development and this seems to fit the bill.
Anyways muds are truly a labour of love and you have to have a few screws loose if you plan to run one. Moreover the glory days have passed (it seems like there many muds shut down en masse around 2000) and in my opinion the community is largely inactive and fragmented. An exerpt from from some of the tba docs sums this up nicely:
So, you're sure you want to run your own MUD? If you're already an
old hand at playing MUDs and you've
decided you want to start one of your
own, here is our advice: sleep on it,
try several other MUDs first. Work
your way up to an admin position and
see what running a MUD is really
about. It is not all fun and games.
You actually have to deal with people,
you have to babysit the players, and
be constantly nagged about things you
need to do or change. Running a MUD is
extremely time consuming if you do it
well, if you are not going to do it
well then don't bother. Just playing
MUDs is masochistic enough, isn't
it? Or are you trying to shave that
extra point off your GPA, jump down
that one last notch on your next job
evaluation, or get rid of that pesky
Significant Other for good? If you
think silly distractions like having
friends and seeing daylight are
preventing you from realizing your
full potential in the MUD world, being
a MUD Administrator is the job for
you.
Anyways I don't have any high hopes for success, but this is something I will find interesting, improve my code-fu and will keep me busy for many years to come :D
There is no active ROM developer mailing list, so tba definitely is a better choice. There was some effort to clean up ROM with the RaM project.
Dead Souls sees active development as well (the main dev is a hero in my eyes for the amount of work he produces).
I would not recommend MUCK as the userbase is rather small. However that is not to say there isn't good work being done -- look up the user Valente on the code subforum of the wora.netlosers.com forum, as he's probably one of the foremost MUCK developers at the moment.
However if you thought that ROM was complicated I should caution you about tackling an established/canon codebase for any purpose other than getting a familiarity with mud servers. For actual development you may be better off with a barebones codebase such as NakedMUD (C/Python) or even something slimmer than that such as Socketmud (ports in many languages).
There are of course dozens of mud servers you can look at; all will be educational in some manner, but in the beginning stages it won't be obvious what is good practice and what is not. You may want to look up ColdC (similar to LP) and TeensyMUD (Ruby) to study. The author of Teensy, Jon Lambert, has a useful developer site up at http://sourcery.dyndns.org/.
However you'll find very experienced ROM and tba (i.e., Circle) developers at MudBytes, and I'll second Sam to say that is the most active mud developer site currently. It's a little surprising but in the last year there has been a significant growth in activity at MB. I think people are coming in from the fold so to speak and gathering at MB. There also is a good-sized code repository at MB as well.
Your other options are The Mudconnector which you already know, Top Mud Sites which has a somewhat smaller crowd of mostly developers (typically of established and long-running muds), and Mudlab, which is much quieter but usually with a good signal to noise ratio. MudGamers is an interesting new site with a fairly quiet forum, but a new approach to creating a more contemporary-looking portal for playing muds.
Not to be overlooked is the archive for the old mud-dev mailing list. There is a staggering amount of information to be gleaned there. The raw archive can be found at muddev.wishes.net/. Richard Tew also has done some noble work in combing through old usenet archives to find valuable mud development related threads, which you can find through his mud tag at posted-stuff.blogspot.com/search/label/mud.
I should note that many muds use the IMC chat network to link muds (MB has a portal to this as well on the front page of their site). Once your mud is running it can be useful to get on IMC if you're in need of real-time chat to fix a problem (of course, there are many IMC channels and you'll want to choose which one you use prudently).
Despite the fact that muds today are niche at best and unheard of at worst, there is no shortage of new muds in development. They offer a design and programming challenge that is still accessible to the solo developer, unlike any graphical game of equal size or complexity.
Furthermore you shouldn't be discouraged if it feels like you'll never release a playable game. Like many larger projects you may start and abandon it many times over, but you'll be building proficiencies across a wide spectrum of programming skillsets and applications -- not many projects will allow you to take such a whole systems approach. Good luck!
An active community seems to be around for the Dead Souls MUDlib
http://en.wikipedia.org/wiki/Dead_Souls_MUDlib
I was an old player of Nightmare LPMud which sadly disappeared. I'm not much in for the coding of these MUDs, but I have been following this community loosely just due to so many positive MUDding memories.
Take a look at Nameless MUCK. It's a solid piece of software.
First concentrate on getting or finding a solid Telnet Socket library going, this is generally the main protocol for a MUD.
Next, create a FULL list of features that you want to implement, you should probably get some sort of feature or bug tracking system setup (even if it is a spreadsheet). Then prioritize the features based on dependencies of other systems.
Check out http://www.gamasutra.com for some architectural discussions on creating games in general, creating basic AI, character systems, and multi-player games.
Once you understand the theory, it is just a butt load of programming to build in everything you want to support.
I'd make the MUD engine abstract enough to run behind both a terminal client, a web-based Ajax client, and maybe stand-alone clients - i.e., don't tie the front end in with the actual game logic. I'm not averse to a MUD actually using a decent font for the text, and real graphics (as interstitials or to make notes on the bulletin board look like notes, etc), not in place of the text based interface) where necessary instead of ASCII, etc.
You might also want to have some MUD script file converters into your own format, so that you don't have to spend ages creating zones.
I find the problem with MUDs is that there is too much emphasis on killing NPCs, and not many puzzles or other interesting aspects. So a more interesting, story-oriented (possibly to the extend of sharding zones for single-player or single-team use) engine could be a nice feature to have.
I will take this opportunity to recommend MudBytes, which is probably the most active MUD developer site available right now.
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When developing an application which mostly interacts with a database, what is a good way to start? The application requires a lot of filtering based on user input, sorting and structuring.
The best way to start is by figuring out "user stories" (or "use cases" -- but the "story" approach tends to really work great and start dragging shareholder into the shared storytelling...!-); on top of that, designing the database schema as the best-normalized idea you can find to satisfy all data layer needs of the user stories.
Thirdly, you may sketch layers such as views on top of the schema; fourthly, and optionally, triggers and stored procedures that might live in the DB to ensure consistency and ease of use for higher layers (but, no matter how strongly DBAs will push you towards those, don't accept their assurances that they're a MUST: they aren't -- if your storage layer is well designed in terms of normalization and maybe useful views on top, non-storage-layer functionality CAN always reside elsewhere, it's an issue of convenience and performance, NOT logical consistency, completeness, correctness).
I think the business layer and user-experience layers should come after. I realize that's a controversial position, but my point is that the user stories (and implied business-rules that come with them) have ALREADY told you a LOT about the business and user layers -- so, "nailing down" (relatively speaking -- agility and "embrace change!" should always rule;-) the data storage layer is the next order of business, and refining ("drilling down") the higher layers can and should come after.
When you get to the database layer you'll want to handle the database access via stored procedures. This will help give you additional protection against SQL Injection attacks, and make it much easier to push logic changes to the database layer.
If it's mostly users interacting with data, you can design using a form perspective.
What forms are needed for user input?
What forms are needed for output reports?
Once you've determined that, the use of the forms will dictate the business logic needed to be coded behind the scenes. You'll take the inputs, create the set of procedures or methods to deal with them, and output what is necessary. Once you know the inputs and outputs, you will be able to easily design the necessary functions.
The scope of the question is very broad. You are expecting me to tell what to do. I can only do a good job of telling how to do things. Do investigate upon using Hibernate/Spring. Since most of your operations looks like querying db, hibernate should help. Make sure the tables are sufficiently indexed so your queries can run faster if filtered based on index fields. The challenging task is design your DB layer which will be the glue between your application and db. Design your db layer generic enough so that it can build queries based on the params that you pass to it. Then move on to develop the above presentation layer. Developing your application layer by layer helps since it will force you to decouple the db logic from the presentation logic. When you develop the db layer, assume that not just your presentation layer but any client can call it. This will help you to design applications that can be scalable and adaptable to new requirements.
So bottom line : Start with DB, DB integeration layer, Controller and last Presentation Layer.
For the purpose of discussion, I'm going to assume that you are working with a starting application that doesn't have a pre-existing database. If this is false, I'd probably move the order of steps around quite a bit.
1 - Understand the Universe
First, you've got to get a sense of what's around you so you can really understand the problem that you are trying to solve.
User stories or use cases are often a good starting point. Starting with what tasks the user will try to do, and evaluating how frequently they are likely to be is a great starting point. I like to start with screen mockups as well, with or without lots of hands on time with users, I find that having a screen gives our team something really finite to argue about.
What other tools exist in this sphere? These days, it seems to me that users never use just one tool, they swap around alot. You need to know two main things about the other tools you users use:
(1) - what will they be using as part of the process, along side your tool? Consider direct input/output needs - what might they want to cut/copy/paste from or to? What tools might you want to offer file upload/download for with specific formats, what tools are they using alongside your tool that you might want to share terminology, layout, color coding, icons or other GUI elements with. Focus especially on the edges of the tools - a real gotcha I hit in a recent project was emulating the databases of previous tools. It turned out that we had massive database shift, and we would likely have been better starting fresh.
(2) What (if anything) are you replacing or competing with? Steal the good stuff, dump and improve the bad stuff. Asking users is always best. If you can't at least understanding the management initiative is important - is this tool replacing a horrible legacy tool? It may be legacy, but there may be the One True Feature that has kept the tool in business all these years...
At this stage, I find that things are really mushy - there's some screen shots, some writing, some schemas or ICDs - but not a really gelled clue.
2 - Logical Entities
Or at least that's what the OO books call it.
I don't care much for all the writing I see on this task - but I find that any any given system, I have one true diagram that I draw over and over. It's usually about 3-10 boxes, and hopefully less than an exponentially large number of lines connecting them. W
The earlier you can get that diagram the better.
It doesn't matter to me if it's in UML, a database logical model, something older, or on the back of a napkin (as long as the napkin is shrouded in plastic and hung where everyone can see it).
The earlier you can make this diagram correctly, the better.
After the diagram is made, you can start working on the follow on work that may be more official.
I think it's a chicken and egg question on whether you start with your data or you start with your screens and business logic. I know that you certianly want to optimize for database sizing and searchability... but how do you know exactly what your database needs are without screens and interfaces giving you a sense for the data?
In practice, I think this is an ever-churning cycle. You do a little bit everywhere, and then you change it all.
Even if you don't get to do a formal agile lifecycle, I think you're best bet is to view design as agile -- it will take many repetitions and arguments before you really feel it's "right".
The most important thing to keep in mind is that your first, and most likely 2nd 3rd attempt at designing the database will be wrong in some way. That might sound negative, maybe even a little rash, (it's certainly more towards the 'agile' software design philosophy) but it's important thing to keep in mind.
You still need to do your analysis thoroughly of course, try to implement one feature at a time, but try to get all layers working first. That way you won't have to do to much rework when the specs change and you understand the issues better. One you have a lot of data loaded into a system, changing things becomes increasingly difficult.
The main benefit of this approach is you find out quickly where you design is broken, where you haven't separated you design layers correctly. One trick I find extremely useful is to do both a sqllite and a mysql version, so seamless switching between the two is possible. Because the two use a different accent of SQL it highlights where you have too tight a coupling between the layers.
A good start would be to get familiar with Multitier architecture
Then you design your presentation layer.
In your business logic layer implement all logic
And finally you implement your data access layer.
Try to setup a prototype with something that is more productive then C++ for example Ruby, Python and well maybe even PHP.
When the prototype works and you see your data model is okay and your queries are too slow then you can start using C++.
But as your questions suggests you have more options then data and in this case the speed of a scripting langauge should be enough.
We have an existing "legacy" app written in C++/powerbuilder running on Unix with it's own Sybase databases. For complex organizational(existing apps have to go through lot of red-tape to be modified) and code reasons(no re-factoring has been done in yrs so the code is spaghetti), so it's difficult to get modifications done to this application. Hence I am considering writing a new modern, maybe grails, based web app to do some "admin" type things directly into the database. For example to add users, or to add "constraint rows".
What does the software community think of this approach of doing a run-around of the existing app like this? Good idea? Tips and hints?
There is always a debate between a single monolithic app and several more focused apps. I don't think it's necessarily a bad idea to separate things - you make things more modular, reduce dependecies, etc.. The thing to avoid is duplication of functionality. If you split off an adminstration app separately, make sure to remove that functionality from the old app, or else you will have an unmaintained set of adminstration tools that will likely come back to haunt you.
Good idea? No.
Sometimes necessary? Yes.
Living in a world where you sometimes have to do things you know aren't a good idea? Priceless.
In general, you should always follow best practices. For everything else, there's kludges.
See this, from Joel, first!
Update: I had somewhat misconstrued the question and thought that more was being rewritten.
My perspective on your suggested "utility" system is not nearly so reserved as would be suggested by my link to Joel's article. Indeed, I would heartily recommend that you take this approach for a number of reasons.
First, this may well be the fastest route to your desired outcome since the old code is so difficult to work with.
Second, this gives you experience with a new development technology and does so in the context of your existing work - this is a real advantage.
Third, I took this approach years ago when transitioning an application from C++ to Delphi. In time, the Delphi app grew to be so capable that a complete leap onto that platform became possible. At no point were users without the functionality that they already knew because the old app wasn't phased out until the replacement functionality had been proven. However, it is at this stage that you'll want to heed Joel's warnings: remember that some of the "messiness" you see is actually knowledge embodied in the old code.
Good idea? That depends on how well the database is documented and/or understood. Make a mistake about some implicit application-level implemented rule, relation, or constraint, and your legacy app may end up doing cartwheels down the aisle.
Take a hypothetical example. Let's say adding a user with the legacy system adds records to the following tables:
app_users
app_constraints
app_permissions
user_address
Let's assume you catch the first three, miss the fourth. It can't be important, right? But what if in the app, in the 50 places that app_users is used, one place does an inner join to user_address. (And why not? The app writer knew that he always wrote a record to user_address!) The newly added user suddenly disappears from the application's view, a condition that "could never happen" according to the original coder, and the application coughs up a hair ball. Orders can't be taken. Production stops. A VP puts his new cardiac bypass surgery to the test.
Who gets blamed? Not the long-gone developer who should have coded for more exceptions. Not the guys who set up the red tape to control change. The guy that did an end run around those controls.
Good luck,
Terry.
Last term (August - December 2008) me and some class mates wrote an application in C++. Nothing spectacular, it is an ORM for Sqlite3. We implemented some stuff like reflection to make it work and release the end user from the ugly stuff. Personally, i think we made a nice job, and that our ORM could actually be useful for someone (even though its writen specifically for Sqlite3, its easily adaptable for oter databases).
Consequently, i`ve come to the conclusion that it should be published somewhere (sourceforge most likely) as an open source project. But, as it was a term project, there are some things that need to be addresesed before doing that. Namely, it has some memory leaks that should be fixed, and some parts of the code could be refactored to make everyone´s life easier in the future.
I would like to know more experienced C++ programmers opinion on some issues:
Is it worth rewriting some parts to
apply new techonologies (for example,
boost).
Should our ORM be adapted to latest
C++ standard? Is there any benefit in
doing this?
How will we know when our code is
ready for release?
What are the chances that this ORM
will be forgotten into the mists of
the internet? (i.e is it worth
publishing it beyond personal pride
as a programmer?)
Right now i can`t think of many more questions, but i would like to read on similar experiences.
EDIT: I should probably translate my code + comments to english right? (self question)
Thanks in advance.
I guess I am "more experienced" with regard to your particular question. I co-developed an open source web application language & template system a lot like ColdFusion back in the early days of web design before Java or ASP were around. You can still see it at http://www.steelblue.com/ if you are interested. It's still used at the company I was at when it was developed, but I don't think anywhere else.
What I found is that unless you are already well connected and people are watching what you are doing, getting people to use your open source code is just about as hard as selling somone your closed source program. You really need to advocate for your project and it should have some kind of unique selling proposition that distinguishes it from the compitition.
So, that's the unsolicited advice. Here are some specific answers to the questions you had...all purely my opinion, of course.
I wouldn't rewrite any code unless you have a featuer you want to put in. That feature might be compatibility with a specific platforms or compilers. It might be to support a new db datatype or smarter indicies or whatever. If you are going to put some more serious work into the applicaiton, think about a roadmap of what you can realistically accomplish in the next iteration and what choices will make the app the "most better" at the end of your cycle.
Release the code as soon as it is usable for a specific purpose, any purpose. Two reasons. First off, there might be someone who wants it for that purpose right now. If it's not available, they will use something else. Also, if it's open source, they might contribute back to the project. Second, the sooner you find out how much people want to use the code, the better. Either it will be more popular than you expect and you can get excited about continuing the development....or....you will find that no one is even visiting your web page to see what you've got. In either case, better to know sooner than later what people really want from your project so you can take that into account when planning new releases.
About the "forgotten into the mists." I think most projects are. I don't want to be a downer, but looking at Wikipedia, there were 5 C++ ORM tools popular enough to get mention and they were all open source. As I said above, unless you can sell your idea to people, they are going to go with another proven open source solution. For someone to choose you over them, three things have to happen: 1. They need a feature you have that the others don't. 2. They find your project web site and it demonstrates the superiority of your code. 3. They trust your code enough to give it a shot.
On the other hand, if you are in this for the long haul and want to continue development thigns get easier over time. Eventually the project will get all the basics covered and you can start developing those new featuers that aren't in the other solutions. Also, the longer you are in active development the more trustworthy the project will seem. Finally, you will get more experience in the nitch. 2 years from now you will be better positioned to say where your effort will have the most impact on bettering the project.
A final thought: If you are enjoying it, learning from it, and it's not getting in the way of you keeping food on the table, it's a good use of your time.
Good luck!
-Al
Regarding the open source part:
If you really want to make it an open source project, you really should publish it regardless of it's current state - fully working and debugged - or half working and full of memory leaks.
Just, if it's state is bad, make sure to document it, and give it a suitable version number (less than one?). then others may view your code, suggest improving, join your team, etc...
My--rather random--thoughts on the matter (in the order I think is most important):
How will we know when our code is ready for release?
Like Liran Orevi said: if you're going open source release early. Document it reasonable well, and take the time to provide a road map of planned or hoped for future improvements (these are a invitation for people to help you, so note which ones have no one working on them).
Is it worth rewriting some parts to apply new technologies (for example, boost).
Should our ORM be adapted to latest C++ standard? Is there any benefit in doing this?
SQLite relies on a fairly limited base. Maybe you don't want your tool to demand a much heavier environment. If the code in not currently a tangled and unmaintainable mess, you might want to avoid boost and newest frills. Once you have a stable release (1.0 at least) you can starting thinking about the improvements that can be made for version 2.
What are the chances that this ORM will be forgotten into the mists of the internet? (i.e is it worth publishing it beyond personal pride as a programmer?)
Most things end up in the big /dev/null in the sky, and there is only one way to find out... If it goes anywhere at all, you win. If it doesn't it was a modest investment, and maybe you learned something while you were at it.