Why use Oracle Application Express for web app?

Question

I believe we\'re moving to Oracle Apex for future development. I\'ve read about Oracle Apex on wikipedia and it\'s pro and con. It seem to me the con outweigh the pro but ma

Answer 1

Don't put buisiness logic into Apex. Use it for presentation only.

If you put the code in the app your will not be able to maintain it, and you'll get RSI from all that clicking. I always create a wrapper layer, and in the oracle world follow Tom Kytes advise - put the business logic as close to the data as possible. This also means that you PL/SQL modules can be called by other systems etc - and best of all - the real meat of your applicaiton will be in straight text files that can be manipulated with your favourite text editor / IDE.

• Create a view with all of the data to be retrieved for each screen.
• Create a single wrapper package for all CRUD operations. (Thats is Create, Read, Update and Delete I presume)

In short:

DO NOT PUT YOUR APP LOGIC IN APEX.

Thats my advise . . . .

Answer 2

That Apex is only suitable for non-programmers and DBAs is an unfortunate misconception. We have used it to build several line-of-business, mission-critical, customer-facing web applications.

The GUI is handled by Apex page templates (HTML), CSS and a bit of Javascript to enhance the user experience. All business logic is placed in PL/SQL packages. This is key to making your application easy to maintain, and to reuse the business logic in other Apex applications and from other client tools, such as C# WinForms, Delphi, Java apps, etc.

As for performance, the Apex engine adds little overhead and the response times and scalability of your application depends largely on the quality of your SQL queries (and the data model). Think about it this way: With Apex, the only thing between your user and the database is a thin layer of PL/SQL. It's only common sense that this has to be faster than a typical .NET or Java application that has seventeen layers of complexity (typically including lots of web services and object-relational mapping layers) between the GUI and the database.

Answer 3

APEX is a framework that uses the database and PL/SQL to produce web pages. If you can figure out what the output to the browser will need to be you can create it in APEX. If you find any part of the framework inhibiting you can write PL/SQL procedures and expose them to the web server directly but still take advantage of the security, logging, session state, etc that the APEX system manages for you.

You should know PL/SQL, SQL, HTML, JavaScript and CSS. Sure the interface looks like a big data entry application but the data you enter will mostly be code snippets in each of these languages.

It scales as well as the database does. It typically uses Apache as a web server but is only used to serve static files and pass requests back to the database, where the web pages are created by the PL/SQL code in the APEX schema. You can use AJAX to minimize the size of the traffic traveling up and down the pipe. You can set caching for specific items, lists, page regions, pages, etc.

Since most things are pretty simple to do with the framework, naturally there will be some things that are a little more complicated to do within the framework. The color coding example given above might be something you do with CSS or maybe you would need to turn to print statements to produce the output you need. The thing is to learn the how the framework makes life easier and then when you hit a limit you can easily resort to more direct methods.

Coming from VB.Net you will miss the step by step debugging and the drag and drop. You will never miss the fact that some part of the page lifecycle will do a bind and reset the values you bound to an object in another part of the page.

Good luck.

Greg

Answer 4

Please note my experiences are with APEX 2.x-3.0.

I used Apex for a few internal apps over a 12 month period but eventually dumped it for ASP.NET.

Some Oracle evangelists claim it is capable of creating highly dynamic content on par with the more mainstream frameworks like ASP.NET/J2EE. Technically this is true, but then technically its also true that you could cross the atlantic in a one man canoe. If you are tempted to throw yourself into a APEX project of even moderate complexity then I suggest you look at the APEX sample of a simple discussion forum. Compare it to an ASP.NET MVC discussion forum sample or a RoR implementation.

Having said that:

The Good

• Incredibly easy to generate a respectable web app with basic CRUD data entry, simple reporting and populate it with data. If you're the IT guy who's been tasked with consolidating a company's mess of Excel/Access dbs into a central DB/web environment then you should take a look at APEX, it very well suited for this task. If you expect the scope to grow to something of even moderate complexity then I would move straight to a more flexible framework.

• If you are a DBA/PLSQL guru but have no experience with traditional web development you'll be well prepped to expose existing business logic in a web app without stuffing around with HTML/CSS/JavaScript if you dont want to.

• APEX support forum has a ton of info and is well staffed by APEX devs.

The Bad

My experience with Apex began to go downhill when apps moved beyond CRUD data entry and required more dynamic and event driven behaviours.

• The web based GUI is not cool. Debugging is painful.

• Version Control? Who needs version control?

• When you (inevitably) need to do anything outside the limited scope of the framework, you'll have to get your hands dirty with PL/SQL. Writing business logic against the database is fine, but generating HTML from PL/SQL procedures felt uncomfortably archaic in 2007.

• Given the large number of sneaky places you can hide page and redirection logic, the program flow is both difficult to visualise and not naturally conducive to modular, separable and reusable code. OOP developers will be not be impressed. It's possible to have well structured maintainable applications with APEX but its harder than it should be. This is worlds away from MVC.

• Unacceptable number of framework bugs in the versions I used. I'd hope this has improved with recent versions, but the paradigm of integrating the IDE into the APEX platform itself caused me some of the darkest, soul destroying debugging sessions of my life. As an example, I was trying to reproduce an intermittent bug that would cause a user to lose their session data. Using the session information popup I saw that occasionally the session data would change when it shouldnt have. I spent 2 days trying to find the error in my code with no luck. Near delirious, I noticed by pure chance that I could reproduce errorous session data in the debug window but the application itself wouldnt go into an error state. My heart sunk when I realised what might be happening. Oracle later confirmed that I'd found a bug in APEX that caused the session information window to intermittently show me data from a prior session. I'd wasted 2 days debugging a session related bug with a buggy session debug window. That was the last Apex app I built.

• PL/SQL is not and will never be the Next Big Thing in web development. After working with APEX for a while I realised it wasnt going to make me a better web developer. Mastering APEX is really about PL/SQL. Thats fine if you plan to focus your career on Oracle technology, just be aware that APEX is so tangential to the direction of mainstream web technologies that the portable set of skills you can take from APEX to other web frameworks is minimal.

If you are considering APEX to provide simple web based data entry and reporting, its worth a look. If you are looking for an alternative to .NET/JAVA/PHP for dynamic web content and rich UI interaction I'd advise you to look elsewhere.

Answer 5

I disagree. It is not only suitable to devs with a few developing skills or DBAs.

We actually produce highly customized apps using CSS templates of our own, a lot of dynamic actions and interaction (using jQuery and several frameworks), fine-tuned security, our own apex plugins and complex PL/SQL processes.

Of course, I am using apex > 4.0.

So, you can build complex apps (we have up to 100 different processes/validations and dynamic actions per pages) if needed. And it could require strong programming skills to code properly in javascript and PL/SQL(OOP) or Java stored procedures + a good knowledge of SQL to define opimized queries of up to 500 lines of code using recursive SQL and some funny features.

Answer 6

I read this page with great interest. Our development team has using Apex for about 2 years now, and I'd like to sum up our experience.

For building basic CRUD applications, Apex really is excellent. In fact I recommend you try it yourself. We did face some initial minor difficulties setting it up, but these seem to have been ironed out in the 3.2 release.

The good

• Great for simple applications. If you app will grow in complexity, consider an alternative solution.
• The built in templates mean your app looks quite professional (although some will debate this).
• A good support forum and community, with plenty of eager people on hand to assist you.
• Some superb built in controls. Love the graphs and reports (but see below).

The bad

• The debugger is abysmal. If you have used Visual Studio (and even ancient versions of Microsoft Access), you will cringe at the debugger. No breakpoints, debug messages spewing out to screen in a big list, having to manually print debug messages to the screen. Horrible. The cause of many, many hours lost to support.

• As soon as your application becomes complex or requires any rich functionality, you have to resort to Javascript and HTML / CSS hacks, which make debugging and support even more complicated (although you can use tools like Firebug or Visual Studio to assist with this).

• We've encountered unexplained session state bugs, and stylesheets becoming 'detached' from the application without explanation - to name a couple of issues.

• Supporting unfamiliar apps can be challenging, as it can be difficult to follow the page logic flow without a good debugger. And I don't buy the stock response of 'well - apps should be coded better'. Because in the real world, they aren't - especially when you're using a contractor.

• Reports look good but not much good if you can't print them or export to PDF. Of course you can shell out for a reporting server, in the end we used another solution.

Overall

I would say by all means use Apex for simple CRUD apps. For anything of more than mild complexity go for .Net or Java. I wouldn't take any notice of the Wiki article on Apex as it's very skewed. Note how 'difficult to debug' (in my opinion the biggest failing) has been erased from the article.

Something to be very wary of as well is the ludicrous claim that you can quickly convert Access databases straight to Apex. Yes it will work if you Access DB is very, very simplistic. Anything moderately complex, forget it, as we found.

We would definitely not use it for web facing apps, only internal. There are simply too many difficulties doing things you would take for granted in say, .Net. I know there are sites out there such as AskTom, but these are not exactly complex. Will we see the next Facebook on it? I think not - although I am sure someone reading this will have a crack at it.

Apex is summed up in a previous comment - managers see the demos, and quickly buy in, convinced that they've found a silver bullet that will slash development times. I've had managers calling me and saying, we need a db app with 40 tables building in a week in Apex please - that's how far the myth has perpetrated. The reality is somewhat different. Yes some things are quicker, substantially quicker, but you will lose the time in other areas - debugging, support, and customisation.

Of course you are best deciding for yourself. Install it, give it a go, you may like it. But don't be fooled by the fast development time claims until you've given it a good going over on a realistic application.