For many Oracle eBS-DBA’s workflow is a strange and hardly understood module.Still it is widely used in 11i and 12i. So let’s dive into its workings in more detail.
This is part one of a so far unlimited series. Don’t be put off by the lack of code in this part. We first need to go through the basics. In the next parts we’ll get more action.
During this series, I used an 11.5.10 instance on a 18.104.22.168 database. The basic statements in these articles will still hold for earlier and later versions, but small modifications may be needed.
In this first part we go into the definitions and the basics of the Workflow engine. We start with some definitions, and then we build a simple basic workflow.
We’ll see how this relates to the wf_tables in the database.
First. What is a workflow? A workflow is a sequence of functions and events that follow a certain path based on decisions made during the progress of the sequence.
Most of us know the pictures from workflow builder. With the pictograms for functions joined together with lines.
That set is a definition of a workflow. In the Oracle workflow world it is called a ‘process’. The nodes in the process can be functions, processes or notifications.
All these are grouped together in containers that Oracle called an ‘Itemtype’. The itemtype is very important, since it will become part of the primary key in the underlying tables.
The actual workflows that are running according to the definition of the itemtype are called ‘Items´. The item is started as a specific process within an ‘itemtype’. And it is uniquely identified by the ‘itemtype’ and an ‘itemkey’.
Every process consists of 2 or more nodes, which are joined together by transitions. At least 2 nodes are required, because a process needs a ’start’ and a ’stop’-node.
Ok. We talked enough for now. Let’s build a process and find out the rest along the way.
By the way, all the definitions above will be linked to a glossary later on.
To start building our process, we first need the itemtype. To create an itemtype, we use ‘Workflow builder’. In workflow builder, when we click the new button we are greeted with this screen:
On right clicking the ‘untitled’ map, we can create a new itemtype.
Internal name is the unique name that will be used in the table keys for this itemtype and its items. It is limited to 8 characters. So choose wisely!
Display name is the name that will be shown to users when they need to interact with items from this itemtype.
The description…….. you can guess that one.
We will discuss the other three fields in a later article.
I choose to start building a flow that will do some DBA checks and tries to fix problems or notify the DBA if there is a problem.
During the course of building this flow, we’ll stumble on different features of the workflow engine.
The first step is to build the itemtype.
I called it: DBA_TYPE.
With a display name: DBA Itemtype
And a description: Itemtype to hold DBA processes and functions.
When you open your newly created itemtype, you see the components that can be created within this itemtype.
You’ll remember that the flow definition was called a process. So next we create a new ‘Process’:
Because this is a process that we will only be calling from our client, we have no use for the result type at the moment.
Later on, we’ll see nested processes, where the result of a process will determine the direction of the calling process.
When we go to the Process Detail (right click the process). We again have a virgin drawing board.
This will be where the actual flow is created. Every process consists of activities (functions, notifications and processes) and the transitions between them (based on the results of the activities).
Also every process has to start with a ‘Start’ Activity and finish with an ‘End’ activity. (Take care to avoid loose ends, since the end finalizes the flow and gives back control, or makes the flow purgeable).
So first we create a new function to start our flow.
Note the wf_standard.noop for the function. This is a dummy function because the only purpose of this node is to indicate the starting point for the process.
Even though we named this function ‘START’, we still need to flag it as a ‘Start’ function. That is in the node tab.
We then create an ‘END’ function in the same way.
Finally we create our own function.
Now we have an item_type with 1 process, and 3 functions. It’s time to connect the functions together.
Right click START, and drag to INITIALIZE_FLOW. Then right click there and drag to END. The result should be like:
Now we have a runnable flow.
You can even start it already, if you create an empty packaged function: ‘ XXX_WF_DBA.init’.
But there is more work to be done.
First we are going to see how this is recorded in the wf_ tables in our database in part 2 of our series.