Skip to main content

Create a Navigation Bar based on a SQL statement

Creating a Navigation Bar using static values is very straightforward. Just create a list similar to this example below - and you can easily define multiple levels.
Then, in the User Interface Attributes, set that list to be your application's "Navigation Bar List" and specify the template.
And the Navigation Bar pops up nicely in the upper right corner of the screen.
So far so good.

But what if you don't want a Static List, but get a list based on a SQL statement? Then you have to enter a statement that adheres to the this structure:
select level, labelValue label, 
       [targetValue]            target, 
       [is_current]             is_current_list_entry,
       [imageValue]             image, 
       [imageAttributeValue]    image_attribute,
       [imageAltValue]          image_alt_attribute,
       [attribute1]             attribute1,
       [attribute2]             attribute2,
       [attribute3]             attribute3,
       [attribute4]             attribute4,
       [attribute5]             attribute5,
       [attribute6]             attribute6,
       [attribute7]             attribute7,
       [attribute8]             attribute8,
       [attribute9]             attribute9,
       [attribute10]            attribute10
from ...
(the columns between the square brackets are optional ones). Adding any other column will fail. But it seems you can enter a "level", so if your query returns the rows in the correct order, you should be fine. You think.
Because doing so (and using the very same List Template) will not work when you have multiple (parent) entries with children: All parents will show the same children, the ones of the first parent. The issue is raised a few times on the Oracle Forums, but never answered (see here and here).

Because I ran into that very same issue this morning, I dived in a little deeper. The problem is in the generated HTML: all buttons (parents) will get the same ID. So that's why the same children are attached to all the parents. 
So where does it get it's ID from? That's defined in the "Navigation Bar" template. In there references to "#LIST_ITEM_ID#" and "#PARENT_LIST_ITEM_ID" are used. But those values are not returned by the query. Even worse, you can't even define columns with those names. 

So the solution is to copy that Navigation Bar Template and replace the references to #LIST_ITEM_ID# and #PARENT_LIST_ITEM_ID# with a column that is returned from the query (and of course contains the right value). So, for instance, use #A09# and #A10# instead of the #LIST_ITEM_ID# and #PARENT_LIST_ITEM_ID# and be sure to select "attribute9" and "attribute10" in your query.
This way you can define a multilevel Navigation Bar based on a SQL statement !


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