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cleanFiles/bookmap_SAP_Commerce_Cloud_Essentials_for_Develope_en-US_learning-sap-com_lsc-prod.zip (MMCP-DROPZONE) - 2024-11-21T07:42:21.000Z

Understanding the Type System in SAP Commerce Cloud

<div id="content"><p tabindex="0">Following a Model-Driven Methodology, the SAP Commerce Type System acts as an intermediary between Java business logic and the database.</p><p tabindex="0">XML type definitions are used to create the corresponding Java classes during the next build, and to generate database tables during the next system update.</p><p tabindex="0">Let’s view the next two videos to:</p><ul style="list-style-type:disc"><li tabindex="0">Explore the concepts and methodology of the SAP Commerce Type System.</li><li tabindex="0">Discover the essentials of items.xml, the (most) important files used to manage the type definitions of the SAP Commerce Type System.</li></ul><p tabindex="0"><strong>SAP Commerce Type System Concept</strong></p><div class="kalturaVideoLessonWrapper"><div aria-label="This video introduces the basic concepts of the SAP Commerce Type System." class="kalturaVideoLessonContainer" data-testid="video" id="1_94z59hwu"></div></div><p tabindex="0"><strong>items.xml File</strong></p><div class="iframe-wrapper"><iframe aria-label="This interactive media describes the structure of the items.xml file." src="/service/media/items_dot_xml_File/story.html" class="storyline_3"></iframe></div></div>

The Type System

Exploring the Technical Essentials of SAP Commerce Cloud

SAP Commerce has to address the best way to access database data.  Object databases are out of the question for performance reasons,  so we need a way to efficiently exchange data between the application layer,  where we use Java objects, and the persistence layer, where we use tables in a relational database.   Conceptually, the SAP Commerce Type System defines abstract entities, the Hybris Type system defines abstract entities, like Product, Category, Order, Price,  Customer,  Page, and so on.  These entities are named item types.  We begin by defining their structure and relationships in an items.xml file.  All the entities used by SAP Commerce are defined as itemtypes, although they’re also called Composed Types,  whose properties can be simple values like integers or strings (defined as atomic types),  collections,  enumerations,  or map types.  In addition, properties can also result from one-to-many, or many-to-many relationships.  The modular nature of SAP Commerce means that every extension, starting with the core extension, can contribute to the definition of these entities, either by adding properties or relationships to existing entities, say Product,  or by creating new entities.  These new entities may extend existing ones, The way VariantProduct extends Product.   In our extension, we might decide to define a new item type, Car, which extends Product.  Every extension can contribute to the type system by including a file called name-of-the-current-extension dash items.xml.  Say you were building the Megacorp website;  your megacorpcore extension would likely contain a file named megacorpcore-items.xml,  where you can modify out-of-the-box types, create new types that extend out-of-the-box types, and define new, standalone types.  The ant process will combine the definition of all these files to establish the final definition of the Type System.  That definition is then used to incarnate these entities as either Java objects or relational tables.  Objects when we’re manipulating them in SAP Commerce,  and tables when we’re storing them for later use.  These Java objects are instances of classes generated by the ant process, using the data found in the combined items.xml file.  The database tables where SAP Commerce will store entity data are created or modified when an initialization or system update is performed.  A major benefit of the Hybris Type System is its ability to cache items. It supports both a query and an item cache, which can significantly reduce the load placed on the database.  You can examine the item types defined on your system by opening the Backoffice and navigating to the Types page, under System.  There, you can view a Composed Type, such as Product.  On the Properties tab, you can view the properties defined for Product,  and the properties it inherits from its supertypes.  You can also view instances of this type from this page,  although common types have their own entries in the Backoffice menu.  When you view a type instance, its properties are usually divided into tabs.  That division is defined in a Backoffice configuration file, and isn’t part of the type definition.  In the next video, we’ll examine the structure of the items.xml file.  Thank you for watching.

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