Skip to main content

Kscope Wednesday

Also today is packed with excellent sessions. The first one, "Cookie Monster", by Tim St.Hillaire covered the different type of cookies and how you can set and read them from within your APEX application. For a lot of purposes you could nowadays use local storage as well, but there's still a case for cookies - and that's not a jar ;-)
The second one, "Single Sign On", by Anton Nielsen was excellent as well. He made clear that just Authentication is not enough: In most cases we need to get back our previous session state as well. A feature that will be included in APEX 5: Session joining. Only in a multi-tenant infrastructure it is not a good idea to enable this as this might open up the possibility to hijack a session. He also explained that from a security point of view, it is important that the APEX authentication is based on both the cookie and the sessionID in the URL.
In session number three, "Pins, Polygons and Perspective", Christoph Ruepprich showed how you can add very nice - and rather easy - geo information to your APEX application. Especially LeafletJS is something to check out, as it is perfect for mobile devices and can use different layers.
After a long break I attended "Production Level Trouble Shooting", especially because I have done sessions on that same subject as well. The key take away is that it is a good idea to instrument your code in a way that you can switch on debugging in a production environment for a single user, a single page and/or a period of time. You can do that - even when debugging is disabled, as it should be - issuing a (conditional) apex_debug.enable command before both page rendering and page processing.
Then, my personal highlight of the day, John Scott did his NodeJS presentation. With some great examples / use cases he made clear that this is something we definitely should check out. With just a few lines of NodeJS code you can create a webserver, a proxy server, create a REST server, create an APEX exporter or a mail reader and websockets server.
The final presentation about APEX URLs by Christian Rokitta gave insight why your URLs should be (more) readable by the user and search engines and some great options and tips how to accomplish this: using intelligent rewrite by either PL/SQL, the ORDS (APEX Listener) and/or by changing the Listener configuration. 

A long, but very interesting day, And now it's time for the big event....

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