Skip to main content

EECS - Oracle Exadate Express Cloud Service, Step 3

Once you have defined your users for your Express Cloud Service, all users with the role of Database Developer or higher can access the database Service Console. From here all database related actions can be started.
The upper category, Web Access, brings you to the specified part of the APEX builder - more on that in the next post. In the lower category you can create database schema's. For our goal within smart4apex, I created a schema for every developer.
You can define whether the schema should be accessible from within APEX and creating an separate tablespace is optional.
I haven't played around with the Document Store yet, so I have to skip that part. You can also set the password of the administrator of your PDB - the most privileged user within your PDB you have access to. Franck Pachot did an excellent writeup about the privileges of that user. I hoped the "Manage Application Express" would bring me to the "APEX Admin" environment - a.k.a. the "INTERNAL" workspace. But in fact it's a very downsized form of that. 
You can enable Application Archiving (using the Application Archive packaged app), enable or disable workspace-to-schema associations and manage a very small number of workspace preferences.
What I had expected and missing the most here is the option to create multiple workspaces! So one EECS instance means one and only one APEX Workspace! I still haven't found the document that lists that limitation. That was a real surprise for me.

The middle part of the Service Console is the most interesting one for this post. As we would like to access our EECS database like a local one! Assuming you have your favorite tool (SQL Developer, SQL Plus or sqlcl already installed), you have to download the "Client Credentials". On downloading you have to enter a password. You'll need that again to set up the connection using SQL Developer. So fire up a a recent version - I used 4.2 - of SQL Developer and define the connection, using "Cloud PDB" as the Connection Type, point the Configuration File to the downloaded zip file and enter the previous defined password. Make the connection and voila, you are running SQL Developer connecting to a 12.2.0.0.3 database in the cloud! 

And while you can do most of the regular database development stuff, there is quite a list of restrictions, limitations and issues, all listed in this document. So no multimedia, spatial, RAS, to name a few.

Connecting with sqlcl is just as simple. Drop the zip-file in a location easy to find by sqlcl (as you can see in the screenshot above, I dropped it in the sqlcl/bin directory). Fire it up with "sqlcl /nolog" and define the cloud configuration using the zip file:

set cloudconfig /Applications/oracle/sqlcl/bin/client_credentials.zip

As you don't want to type that line each and every time, it's convenient to put that in a login.sql file in the sqlcl directory. 
The zipfile is unzipped in a new directory on your file system - it seems to create a new directory each and every time you issue that command. I hope it gets cleaned up somewhere somehow eventually ...

And is it fast? It feels pretty fast - hey it is an Exadata machine  - , but now and then I noticed some latency in the connection. Not too bad and expected as the server is in the US. I'm sure that will be a lot better once there will be a real European roll-out. In the Service Console there is a little diagnostics tool hidden in the menu in the upper right corner where you can measure your latency. I measured it three times and the latency was around 180ms on average. So that's not super, but not really annoying in a sqlcl / SQL Developer environment. But what would happen if I start clicking around in the APEX Builder?

Comments

Popular posts from this blog

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

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

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