Roels Blog

 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 ...

Almost every APEX Developer knows that JavaScript and CSS belongs in separate files and (in 99% of the use cases) not somewhere in your Page properties. If you have this code in separate files it is easier to use them in a Version Control System (SVN or Git) - if the files are outside of APEX. And the code you store in these files can be reused, in contrast to the stuff you store on Page level. In a lot of environments it is harder to use external files, because deployment of these files to the appropriate location on a webserver requires special privileges that not everybody has. In those cases storing these files as Static Application Files or Static Workspace Files might be a better solution. It makes deployment easier, because these files will be exported and imported as part of the application. You can't accidentally forget about them. But working with these files is quite a pain. When you need to edit something you have to download that file, make the changes, upload it again...

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...

There are some, maybe rare, use case when you want to set the " Suppress Change Event " switch of a Dynamic Action to " Yes ". Usually that's only necessary when the Dynamic Action is fired On Change  and executes a Set Value  with the same field as a target. There might be a chain of events leading to this or just one. If you forget to set it you'll end up in an endless loop and your browser will choke. That works all fine and as expected with regular Page Items. However ... when you apply this to a column in an Interactive Grid something unexpected happens. When you set the Suppress Change Event of a Dynamic Action that fires on change of a column to Yes , the value of that item seems empty when you leave that field (column)! If you navigate back into that field, the (new) value does show up... You can call it a feature, you can call it a bug, but bottom line it is unexpected and undesired behaviour. The solution is to call the Grid method SetActiv...

The APEX Interactive Grid uses the Toolbar widget to create the default Toolbar showing the Search box, Actions menu, Save button etc. And since quite a while there is a nice Plugin " Extend IG Toolbar " by Marko Goricki that makes it very easy to add additional buttons to the Toolbar. But what if you need more than a button?  Inspecting the contents of widget.toolbar.js, you can easily spot there can be added more to the Toolbar than just a button: The type of control, available values: "STATIC", "TEXT", "SELECT", "BUTTON", "MENU", "RADIO_GROUP", "TOGGLE". The first example will show a way to easily switch from one filter to another. Of course we could use the standard functionality and create two different Report views, but using a Radio Group on the Toolbar gives a more "Tab" like user experience. So how can we create a Radio Group that looks like a switch in the Toolbar? In...

If you are using multiple containers to set up your Oracle Development (or Test or Production) environment - as I described here - you probably ran into the issue that your ORDS container was started before the Database was started up. This results in an ORDS container that is not working - at least not as you need to. Using Docker Compose you can specify a depends_on option, for instance in the ORDS container configuration you specify (where "oracle" refers to the container that holds the Oracle database) : depends_on : - oracle but this only means the ORDS container will start after the "oracle" container has been started. That does not mean the Oracle database inside the container is started and available! So how do we tell the ORDS to configure itself in one container to wait for the database in another container is ready to use? Step 1: Start the Oracle database (container), connect to it and enable a port - in this example 8080 - in the...