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Create Parent-Child Hierarchies in SAP Data Warehouse Cloud

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Create Parent-Child Hierarchies in SAP Data Warehouse Cloud
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Create Parent-Child Hierarchies in SAP Data Warehouse Cloud

October 11, 2021
Created by
October 10, 2021
Create a parent-child hierarchy (PCH), a hierarchy in a standard dimension that contains a parent attribute.

You will learn

  • How to create a parent-child hierarchy in SAP Data Warehouse Cloud
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Prerequisites


Step 1: What is a parent-child hierarchy

A parent-child hierarchy (PCH) is a hierarchy in a standard dimension that contains a parent attribute. A parent attribute describes a self-referencing relationship, or self-join, within a dimension main table. In other words, child and parent tables are just normal database tables, but linked in a way that describes a special relationship: a parent-child relationship. This is used most often when one table’s value refers to the value in another table (usually a primary key of another table).

For instance, most profit and loss statements have a native parent-child hierarchy for representing the list of accounts. Also, a list of components of a product, a car for instance, usually is a native parent-child hierarchy because each component has other sub-components, with different levels of depth in different branches of the hierarchy. And, of course, organizational structures of companies, are often represented as parent-child hierarchies, as well.

One of the limitations of a parent-child hierarchies is that each node (item, name, etc.) must have a single parent. Complex organisations, of course, don’t respect this constraint and require more complex graphs. Mapping these graphs to a parent-child hierarchy has to be proceeded by the normalisation to a regular organisation tree.

A few constraints of a parent-child hierarchy include:

• A dimension containing a parent-child hierarchy cannot include any other hierarchies.

• The attributes used for the parent key and member key cannot be composite keys.

• If the imported data source contains hierarchy members with multiple parents, you can use surrogate keys in the data source to overcome this issue.

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Step 2: Create a parent-child hierarchy
  1. In order to create a hierarchy within your dataset, you need to ensure that your uploaded CSV files have their datasets defined properly. Go into the Data Builder, and select your uploaded CSV file. Ensure that the data types of your target columns are of the right type.

    Data Type
  2. The next step is defining your table as a dimension. A dimension is where you identify a set of master data attributes and keys for use in fact and consumption models. Hence, your table must be defined as such. On the same screen, click on the Semantic Usage drop down and select Dimension.

    Semantic Usage
  3. A hierarchy icon shaped like a staircase now becomes selectable on the top bar. Click on this icon to open the hierarchy settings.

    Hierarchy Icon
  4. Click on the + icon and select Parent-child hierarchy.

    Add
  5. You can now define the business name, technical name as well as the parent and child in your parent-child hierarchy. In this example, the parent column is given as the company, and the child column is given as the email address of the employee. Click on Close once done.

    Define Names
  6. As always, first save and then deploy your dataset. Your dataset is now ready to be combined with analytical datasets to produce a clear and concise visualisation with well defined hierarchies.

    Save and Deploy

Well done!

You have completed the 1st tutorial of this group! Now you know how to create a parent-child hierarchy in SAP Data Warehouse Cloud.

Learn in the next tutorial how to create a level-based hierarchy in SAP Data Warehouse Cloud.

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Step 3: Test yourself
Can a parent-child hierarchy also contain other hierarchies?
×

Next Steps

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