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cleanFiles/bookmap_Developing_Analytical_Queries_using_CDS_Pr_en-US_learning-sap-com_lsc-prod.zip (MMCP-DROPZONE) - 2025-02-14T11:40:23.000Z

Exploring the Star Schema

<div id="content"><p tabindex="0">A star schema contains many relationships between data elements and it is difficult to get the full picture of the data model by navigating through the code. The tool <strong>Relation Explorer</strong> can be used to find your way around the star schema and observe all the connected objects.</p><p tabindex="0">The Relation Explorer is part of the ADT tools of Eclipse. The Relation Explorer is a popular tool used in a wide range of ABAP development scenarios.</p><p tabindex="0">You launch the tool using <i>Show In</i> → <i>Relation Explorer</i>.</p><img style="max-width:900px;max-height:none" class="image 1_1_landscape" title="Relation Explorer, highlighting the current context and how to change the context" alt="Relation Explorer, highlighting the current context and how to change the context" src="/service/media/S4D433_26_en-US_media/S4D433_26_en-US_images/relation_explorer_image.png" tabindex="0"><div class="imageCaption"></div><p tabindex="0">The tool is used in different development scenarios, so it is important to set the context of the tool usage to provide the information you are interested in. To explore a star schema you should use the context <i>analytics</i>. You can set the context manually using the drop-down selector button that only appears alongside the tab. If you launch the tool from a CDS view with <i>dataCategory: #CUBE</i> or <i>dataCategory: #DIMENSION</i>, the context is automatically set to <i>analytics</i>.</p><div class="kalturaVideoLessonWrapper"><div aria-label="" class="kalturaVideoLessonContainer" data-testid="video" id="1_foux9qn9"></div></div><p tabindex="0">The <i>Relation Explorer</i> is a tool that is especially useful to the developer of analytical queries so they can discover the available elements of the underlying cube that they plan to consume.</p></div>

Relation Explorer

Developing Analytical Queries using ABAP Core Data Services

Learn how to explore and analyze your data model using the Relational Explorer tool in ADT. Understand the structure of your cube, dimensions, measures, and more. Enhance your CDS analytical projection views.<br><br># This description was auto-generated #

relation_explorer_video.mp4

Before you begin creating your CDS analytical projection views, it's a good idea to be familiar with the underlying data model, that is the star schema. Now there's a great tool called the relational explorer in the ADT tools and you can use that to basically explore your model. Now this is relevant for any types of views with the data category cube or dimension. So to get started, what you need to do is to right click anywhere in the code of the data model. In this case, this is our flight cube. And then open up the option which is to show in a relational explorer. A new pane opens up now as is at the bottom. So let's stretch it up a little bit here. And notice now you see the relational explorer tab. It's made up of two sections. So there's a left side and a right side. And on the left side, you get the overall view of the cube. Starting with the top, there's the cube, and you can see as you look down, those are the dimensions listed. Now on the right side, this is the detail of what you have clicked on on the left. So we've clicked on the cube on the left, which now shows us the detail on the right pane. And you can see here a breakdown of the components of the cube. So we start off with the dimensions, and we have a nice neat list of dimensions. Then that's followed by the measures, followed by the units. If we look at the list of dimensions, you will see for each dimension, there's some useful information given. So to the right of airline ID, we see the label, which is airline space ID. Then we see text, which means that there is a text view available, and then we see attribute, which means a dimension view is available for this dimension. If we go further down to connection ID, let's take a look at that one. That one's got a label flight number, but only an attribute means a dimension view, no text view this time. And then further down, if we look at departure airport ID, notice the label departure airport. For this one, there's text view, dimension view, and also now a hierarchy view as well. And we can even expand each dimension to get further information. For example, the association tells us the actual associated view for this one here. So this one is of course the dimension view by airport. And we look further down, this one is interesting because flight year also includes some time-based information. We can see this one is based upon a calendar year, so we know it's a year format, and it's also derived from the flight dates, a year comes from the date. And we can look at the top here at the basic view code, and we can see where that flight year comes from, and then you can see how the alignment of that information comes from the code. And you can see these annotations are determining those parameters you just saw. So let's take a look at the measures and we'll take the first one, distance. If we double click on that, it shows us in the source code where that appears. And you can see here that the connection distance is A list as distance. And you'll notice that the aggregation value is sum. So let's now take a look at the other views in the model. So if we look on the left pane, we can double click on the dimension view airport. The top of the screen, we see the original source code of that view. And then in the bottom right pane, in the relational explorer, we can see the most important information summarized. We see the key of the dimension view is the airport ID. And then below that we see each individual attribute listed. Notice we can also see down at the bottom, we have a text element as well. So this has been marked to be treated as text and not an attribute.