The Union Transformation in Informatica is used to combine data from multiple sources (excel files, flat file etc) or multiple SQL tables and produce one output to store in the target table. This transformation is an active transformation and it is similar to the SQL Union All.
The Union Transformation in Informatica is very useful in real-time, for example if the company has 100 stores and each store maintain their own sales data. End of the day they all belongs to one company and your job is to find out the one month or year sale for any single product. It is not practical to visit 100 stores or cross checking 100 excel or flat files and calculating the sales. In this situations all you have to do is, use Union Transformation in Informatica to combine all the 100 excel files from 100 stores and store it in the data warehouse and then, calculate the product sales from the database.
Union Transformation in Informatica Guidelines
Please remember the following guidelines while you are working with the Union Transformation:
- Union Transformation allows multiple input groups but produce single output.
- It doesn’t remove duplicate records from the input source.
- This transformation doesn’t generate transactions.
- You can not use Sequence Generator Transformation to generate sequences
In this article we are going to explain the steps involved in configuring the Union Transformation in Informatica with example. For this example, we are going to use the SQL tables that we created using the Router Transformation.
Following screenshot will show you the data inside the [Router 1] table.
Following screenshot will show you the data inside the [Router 2] table.
Following screenshot will show you the data inside the [Router 3] table.
Here, Our task is to combine these three tables using the Union Transformation and save it in the destination table.
Configure Union Transformation in Informatica
Before we start configuring the union transformation in informatica, First connect to Informatica repository service. In order to connect with Repository service we have to provide the Informatica Admin Console credentials so, Please provide the appropriate Username and Password and click on Connect button as shown below.
TIP: Here you have to provide the Admin Username and password that you specified while installing the Informatica Server.
Step 1: Creating Source Definition
Once you connected successfully, Please navigate to Source Analyzer and define your Sources. In this example, we are using [Router 1], [Router 2] and [Router 3] tables from SQL Server database as our source definitions. Please refer Database Source in Informatica to understand the steps involved in creating source definition
Step 2: Creating Target Definition
Please navigate to Target Designer and define the Target. In this example, we are using the already created SQL table (Union Transformation) as our target definitions. Please refer Create Informatica Target table using Source Definition to understand the steps involved in creating target definition
Step 3: Creating Mapping
In order to create new mapping, Please navigate to Mappings menu in Menu Bar and select the Create.. option. This will open the Mapping Name window as shown below. Here, you have to write unique name for this mapping (m_Union_Transformation) and click OK button.
TIP: Please refer Informatica Mapping article to understand the steps involved in creating Mapping.
Next, Drag and drop the [Router 1], [Router 2] and [Router 3] source definitions from Sources folder to the mapping designer. Once you drag the source, PowerCenter designer will automatically create the default transformation called source qualifier for them.
Step 3(a): Creating Union Transformation in Informatica
In order to create Union transformation in informatica, Please navigate to Transformation menu in Menu Bar and select the Create.. option as we shown below.
Once you click on the Create.. option, Create Transformation window will be opened as shown below. Please select the Union Transformation from drop down list and specify the unique name (UN_Products) for this transformation and click on Create button
Once you click on the Create button, union transformation will be added to the mapping designer. In order to perform union all, Union Transformation requires some data so, please connect the Router 1 Source qualifier with the transformation by dragging the required fields. Once you drag the fields, transformation will create OUTPUT Group and New Group.
In order to merge more than one table, we need multiple groups like NEWGROUP so, Double click on the Union transformation to create new groups. From the below screenshot you can see the list of available properties in Transformation tab:
- Select Transformation: By default it will select the transformation you clicked on.
- Rename: This button will help you to rename the union transformation to more meaningful name.
- Make Reusable: If you check mark this option then, this transformation will become reusable transformation.
- Description: Please provide the valid description about this transformation.
Within the Groups tab we have to define the group names. Please click on the New Group button (beside the close button) to add new group and change the names as per your requirements. By clicking the close button you can delete the unwanted groups. From the below screenshot you can observe that we created three groups Least Sales, Medium Sales and Highest Sales.
Once you finish creating the Groups, Click OK to close the transformation window.
Next, w have to assign the Source Qualifiers to the new groups that we created earlier. so, please connect the Router 2 Source qualifier with the Medium Sales and Router 3 Source qualifier with the Highest Sales
Next, Drag and drop the target definition (Union Transformation) from Targets folder to the mapping designer and connect the Transformation with the target definition. Please use the Autolink.. option to connect them.
Before we close the Mapping, Let us validate the mapping by going to Mapping Menu bar and selecting the Validate option.
Step 4: Creating Workflow
Once we finish creating the Mapping we have to create the workflow for it. PowerCenter Workflow manager provides two approaches to create workflow.
In this example we will create the Workflow manually. In order to create new Informatica Workflow, Please navigate to Workflows Menu and select the Create option. This will open Create Workflow window as shown below. Please provide the unique name (wf_Union_Transformation) and leave the default settings.
Once we created the workflow, our next step is to create session task for our mapping.
NOTE: We strictly recommend to refer Informatica Workflow article to understand the steps involved in creating Workflow manually.
Step 4(a): Creating Session
There are two types of sessions in informatica:
- Non-reusable Session Task: Please refer Session in Informatica article to understand the steps involved init.
- Reusable Session Task: Please refer Reusable Session in Informatica article to understand the steps involved init.
For this example we are going to create Non-reusable Session. Please navigate to Tasks Menu and select the Create option to open the Create Task window. Here you have to select the Session as Task type (default) and enter unique name (S_Union_Transformation) for the session.
Once you click on the Create button, a new window called Mappings will be opened. Here you have to select the mapping you want to associate with this session. From the below screenshot you can observe that, we are selecting the mapping (m_Union_Transformation) that we created earlier (in Step 3).
Double click on the Session Task to configure it. Although we have to configure Sources, targets and some common properties, we are explaining only few properties. We strictly recommend to visit Session in Informatica article to understand the remaining properties.
From the below screenshot you can observe that, we assigned the $target variable to Connection Value, we check marked the Truncate target table option to truncate the existing data from the destination table.
From the below screenshot you can observe that the Router Transformation in Informatica workflow is a valid one. Now, Let us start the Workflow by navigating to Workflows menu and selecting the Start Workflow option.
Once you select the Start Workflow option, Informatica PowerCenter Workflow monitor will be opened to monitor the workflow. From the below screenshot you can observe that, our workflow is executed without any errors.
Let us open the SQL Server Management Studio check whether we successfully combined the records present in Router 1, Router 2 and Router 3 tables or not
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