By Krishna Sai Geetla, HEXstream data analytics engineer

Let's explore how to modify existing subject areas by creating metrics in existing subject areas. We can create a new metric in “My calculations” in OAC and verify results of both SME and OAC metric matched.

Goals:
1) To verify if users can add a new calculation in existing subject area's fact by using simple calculations/limiting expressions and using columns from logical dimensions and the fact itself in the SME sandbox.
2) To verify if the same calculation created in SME can also be created as a custom calculation in the "my calculations" tab from the OAC subject area folder.
3) Ensure that the final verification is in reports whether the two metrics from SME and OAC yield the same result.

Flow of steps:

·      In the FDI console click on Semantic model extensions.

·      In user extensions click on create a sandbox.

·      Give a name to the sandbox and click on done.

·      After clicking done user will be taken to new window where we can manage logical star and subject area.

·      Click on perform action and then on manage logical star.

·      As this use case is on existing subject area click on edit logical star>check on out of the box>select the subject area name>select the fact and click on next.

·      In the new window user can see the logical star structure.

·      As we are adding a new metric on fact , right click on the fact and then on manage extension.

·      In the next window click on manage dimension and select add columns in the drop down.

·      Click on the “add derived column” option.

·      Here we can add the content of the calculation. 

·      There are options to select analytical functions on the right side for any calculations or user can directly type in the code.

·      Here we are validating a calculation based on a filter.

·      To select which columns need to be added in the calculation, users must select from the dropdowns od current data elements to select from same fact or from other data elements where users can select from existing dimensions or calendar dimensions.

·      To select a column from dimensions, users can click on logical tables> expand the required dimension and double click or drag and drop the desired column.

·      As this is a filter expression, we type in the limiting value for calculation as "Residential."
(Values in a dimension/fact cannot be selected. User must give the details.)

·      Entering name of the new metric is mandatory.

·      After giving name, check on the validate option to see the calculation expression is correct and click on save.

·      After clicking save, users are taken to other screens where metric details are present. Validate and click on finish.

·      Users can see the add col after clicking finish. After viewing, click on the back arrow.

·      Click back from the logical star-structure screen.

·      Logical star changes are done now. 

·      Click on perform action to modify subject area with new changes.

·      Select manage subject area.

·      Select modify existing subject area> select the name > and click on next.

·      In the next wizard of the Modify Subject area, click on next after confirming that the folders of the existing subject area are going to be modified.

·      In the next wizard, click on the manage-elements drop down and select manage factory customizations.

·      Check the new metric that must added to the subject area and click on add folders.

·      Select the fact name to add folder and click on add folders.

·      Cross check on the selected data elements with the new changes and click on finish.

·      After the subject area changes, go back to the previous page of user extensions.

·      Click on the sandbox options to apply changes.

·      Verify the task by going to activity page.

·      After changes are applied on sandbox, click on publish model and select the sandbox name. Then click on publish.

·      Check the task updates in Activity.

·      After confirming the publishing of user extensions in Sandbox, go to OAC page by clicking on home page in Main FDI console or through OAC URL.

·      Click on the dropdown to select the data option.

·      Search and select the subject area name.

·      Verify if the new column change is added to the folder.

·      Use the calculation to check data by double clicking on a column or by the drag-and-drop method.

·      The other part of the use case is to verify the same calculation done in SME by creating a calculation in OAC.

·      For that verification, right click on my calculations and select create calculation.

·      Just like in SME in OAC, we can use the in-built analytical expressions or type-in.

·      But to select a column, we must hover to the desired fact/dimension and double click or drag-and-drop on the column.

·      We select “other amount” from fact and “customer class” from account dimension and limit customer class to ‘Residential’.

·      Give the name of calculation and click on validate to see for any errors>then click on save.

·      Verify the data of the calculation from My Calculations by double-clicking on it.

·      We can verify that the SME calculation and the OAC calculation is the same.

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