Association Rules in ODM–Part 1

This is a the first part of a four part blog post on building and using Association Rules in Oracle Data Miner. The following outlines the contents of each post in the series on Association Rules

1. This first part will focus on how to building an Association Rule model
2. The second post will be on examining the Association Rules produced by ODM – This blog post
3. The third post will focus on using the Association Rules on your data.
4. The final post will look at how you can do some of the above steps using the ODM SQL and PL/SQL functions.

The data set we will be using for Association Rule Analysis will be the sample data that comes with the SH schema in the database. Access to this schema and it’s data was setup when we created our data mining schema and ODM Repository.

Step 1 – Getting setup

As with all data mining projects you will need a workspace that will contain your workflows. Based on my previous ODM blog posts you will have already created a Project and some workflows. You can either reuse an existing workflow you have used for one of the other ODM modeling algorithms or you can create a new Workflow called Association Rules.

Step 2 – Define your Data Set

Assuming that your database has been setup to have the Sample schemas and their corresponding data, we will be using the data that is in the SH schema. In a previous post, I gave some instructions on setting up your database to use ODM and part of that involved a step to give your ODM schema access to the sample schema data.

We will start off by creating a Data Source Node. Click on the Data Source Node under the Component Palette. Then move your mouse to your your workspace area and click. A Data Source Node will be created and a window will open. Scroll down the list of Available Tables until you find the SH.SALES table. Click on this table and then click on the Next button. We want to include all the data so we can now click the Finish Button.

Our Data Source Node will now be renamed to SALES.

Step 3 – Setup the Association Build Node

Under the Model section of the Component Palette select Association. Move the mouse to your work area (and perhaps just the to right of the SALES node) click. Our Association Node will be created.

For the next step we need to join the our data source (SALES) with the Association Build Node. Right click on the SALES data node and select Connect from the drop down menu. Then move the mouse to the Association Build node and click. You should now have the two nodes connected.

We will now get the Edit Association Build Node property window opening for us. We will need to enter the following information:

• Transaction ID: This is the attribute(s) that can be used to uniquely identify each transaction. In our example the Customer ID and the Time ID of the transaction allows us to identify what we want to analyse by i.e. the basket. This will group all the related transactions together
• Item ID: What is the attribute of the thing you want to analyse. In our case we want to analyse the Products purchased, so select PROD_ID in this case
• Value: This is an identifier used to specify another column with the transaction data to combine with the Item ID. <Existence> means that you want to see if there are any type of common bundling among all values of the selected Item ID. Use this.

Like all data mining products, Oracle has just one Algorithm to use for Association Rule Analysis, the Apriori Algorithm.

Click the OK button. You are now ready to run the Association Build Node. Right click on the node and select Run from the menu. After a short time everything should finish and we will have the little green tick makes on each of the nodes.

 

Check out the next post in the series (Part 2) where we will look at how you can examine the rules produced by our model in ODM.