Skip to main content

ODTUG Kaleidoscope 2008 : The pre-conference conference


The day started with a rather fierce thunderstorm, and I can tell you that if it rains in New Orleans it really rains! This day was a sort of warming-up for the real conference with three full day symposiums on Essbase, APEX and Fusion. I attended the ‘The Seasoning of Application Express - Must hear Succes Stories‘ symposium that started off with an impressive presentation of Scott Spendolini. His theme was ‘Less is more‘, what didn’t refer this own presentation as he managed to go to 431 slides in half an hour! After that Mike Hichwa from Oracle did an ‘Apex Update’. He told us that currently APEX is the most used tool within Oracle for internal applications. Oracle also releases products that are based on APEX, like Database Vault. And we got a sneak preview of the future of APEX: we will get updateable interactive reports, custom item types, easy way to attach files of any kind to a record and declarative AJAX support. And some other good news: SQL Developer will support logical and physical data modeling - so we don’t need Designer for that anymore. And from these datamodels APEX applications can be generated using templates.

The other five presentations were user experiences. They all come together at one point: Application development can be incredibly fast when you use APEX, and that’s exactly what the business needs: short term to market and agile development. The IT departments have some difficulties in this paradigm shift: the regular long term waterfall approach doesn’t work here. And the risk is that the business users will develop the applications themselves (again, just like they did using Excel and Access), just because it is - or seems to be - so easy.

Just before the Welcome Reception Thomas Kyte did a presentation on ‘How do you know what you know…‘. It was the same message as he delivered 1,5 year ago during Open World, but with different examples: Knowledge is good, but can also be bad. If you had an experience in the past, that doesn’t automatically mean it still counts, because things, like the Oracle database, change. BTW it’s always a great pleasure to attend one of Thom’s presentations.

Comments

Popular posts from this blog

apex_application.g_f0x array processing in Oracle 12

If you created your own "updatable reports" or your custom version of tabular forms in Oracle Application Express, you'll end up with a query that looks similar to this one: then you disable the " Escape special characters " property and the result is an updatable multirecord form. That was easy, right? But now we need to process the changes in the Ename column when the form is submitted, but only if the checkbox is checked. All the columns are submitted as separated arrays, named apex_application.g_f0x - where the "x" is the value of the "p_idx" parameter you specified in the apex_item calls. So we have apex_application.g_f01, g_f02 and g_f03. But then you discover APEX has the oddity that the "checkbox" array only contains values for the checked rows. Thus if you just check "Jones", the length of g_f02 is 1 and it contains only the empno of Jones - while the other two arrays will contain all (14) rows. So for

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 old Employ

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