Expert Oracle Application Express

I have just seen half of the chapters in this upcoming book. And I only can say: WOW! The content of this book is just so good. So this is definitely a must-have! You can pre-order it already (click here). And - again - all revenues go to charity....

Comments

John Scott said…

and you forget to add that you wrote one too ;)

John.

10:08 am

Stew said…

If only they'd ship it! I ordered it from Amazon.com back when it was first announced, but they say it won't ship until the 24th. If I had an Apex project in the works, I'd be drooling for it. Sadly, I don't have anything Apex-bound on the horizon.

But that's one of the beauties of digital books. I can get this now via Apress.com's Alpha program.

1:46 pm

Buzz Killington said…

So if all the money goes to charity, do I get a tax exemption for buying this?

4:47 pm

Roel said…

@Buzz : You can save the receipt and use it for your tax declaration ;-)

4:52 pm

Stop using validations for checking constraints !

If you run your APEX application - like a Form based on the EMP table - and test if you can change the value of Department to something else then the standard values of 10, 20, 30 or 40, you'll get a nice error message like this: But it isn't really nice, is it? So what do a lot of developers do? They create a validation (just) in order to show a nicer, better worded, error message like "This is not a valid department". And what you then just did is writing code twice : Once in the database as a (foreign key) check constraint and once as a sql statement in your validation. And we all know : writing code twice is usually not a good idea - and executing the same query twice is not enhancing your performance! So how can we transform that ugly error message into something nice? By combining two APEX features: the Error Handling Function and the Text Messages! Start with copying the example of an Error Handling Function from the APEX documentation. Create this function ...

Filtering in the APEX Interactive Grid

Remember Oracle Forms? One of the nice features of Forms was the use of GLOBAL items. More or less comparable to Application Items in APEX. These GLOBALS where often used to pre-query data. For example you queried Employee 200 in Form A, then opened Form B and on opening that Form the Employee field is filled with that (GLOBAL) value of 200 and the query was executed. So without additional keys strokes or entering data, when switching to another Form a user would immediately see the data in the same context. And they loved that. In APEX you can create a similar experience using Application Items (or an Item on the Global Page) for Classic Reports (by setting a Default Value to a Search Item) and Interactive Reports (using the APEX_IR.ADD_FILTER procedure). But what about the Interactive Grid? There is no APEX_IG package ... so the first thing we have to figure out is how can we set a filter programmatically? Start with creating an Interactive Grid based upon the good o...

Refresh selected row(s) in an Interactive Grid

In my previous post I blogged about pushing changed rows from the dabatase into an Interactive Grid . The use case I'll cover right here is probably more common - and therefore more useful! Until we had the IG, we showed the data in a report (Interactive or Classic). Changes to the data where made by popping up a form page, making changes, saving and refreshing the report upon closing the dialog. Or by clicking an icon / button / link in your report that makes some changes to the data (like changing a status) and ... refresh the report. That all works fine, but the downsides are: The whole dataset is returned from the server to the client - again and again. And if your pagination size is large, that does lead to more and more network traffic, more interpretation by the browser and more waiting time for the end user. The "current record" might be out of focus after the refresh, especially by larger pagination sizes, as the first rows will be shown. Or (even wors...

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