Data Model Overview | Hybris Academy

Overview

Data modeling in Hybris is the process of defining the structure and relationships of data entities within an e-commerce system. Data modeling is a crucial step in building and customizing an e-commerce solution as it determines how data is organized, stored, and accessed within the system. Here are the key aspects of data modeling in Hybris:

Entity Definition: In Hybris, data modeling begins with defining the various entities or objects that the e-commerce system needs to manage. These entities can include products, categories, customers, orders, payments, and more. Each entity corresponds to a specific type of data that the system needs to store and manipulate.
Attributes: For each entity, you define attributes that represent the properties or characteristics of that entity. Attributes can be of various data types such as strings, numbers, dates, and enumerations. For example, a product entity may have attributes like product code, name, description, price, and availability.
Relationships: Data modeling also involves specifying relationships between entities. This defines how different entities are related to each other within the system. For instance, a product may be associated with one or more categories, and a customer may have multiple orders. These relationships help organize and retrieve data efficiently.
Constraints: You can specify constraints on attributes and relationships to enforce data integrity rules. For example, you can ensure that certain attributes are mandatory or that values in a specific attribute are unique.
Enumeration Types: Enumerations allow you to define a fixed set of values that an attribute can take. This is useful for attributes like product status, where the values might be limited to "In Stock," "Out of Stock," etc.
Database Schema: Hybris automatically generates the database schema based on your data models. It creates the necessary tables, columns, and indexes to store the data in the database

Type System

The Type System is a fundamental concept used to define and manage the structure of data entities or items within the system. It provides a structured way to define and organize various data types and their attributes. The Type System serves as a foundation for data modeling and management in Hybris.

Types define an objects for manage and store data with Java implementation.

JAVA: Object is instance of Class and Class is blueprint of Object.

HYBRIS: Item is instance of Type and Type is blueprint of Item.

Data model types in Hybris:

Atomic types: They are the simplest and most fundamental data types used in data modeling. For example define an Item type called Product, and within that type, define attributes like code (String), price (Double), inStock (Boolean), and creationDate (Date/Time).
Collection Type: Collection types are used to define attributes that can hold multiple values.For Example creating a collection type for a shopping cart that can contain multiple CartEntry instances.
Enumeration Type: Enumeration types allow you to define a fixed set of values that an attribute can take. For example defining an enumeration type for product statuses with values like "In Stock," "Out of Stock," etc.
Map Type: Map types is used to have key values pairs in Hybris data modeling. For example simple Product Configuration item type that stores product configuration options as key-value pairs.
Relation Type: They specify how different item types are related to each other. For example establishing a relation type to associate Product items with Category items.
Item Type: It represents a specific entity or object in your e-commerce system. For example defining a Product item type with attributes like code, name, and relationships to other item types like Category.

Item.xml : The items.xml file is an important configuration file used to define the data model of your e-commerce solution. It is an XML file that contains definitions for item types, attributes, relationships, constraints, and other metadata related to the data structure of your application. you can define new types ,override and extend existing types.

For example:

For the core extension, the file is called core-item.xml.

For the facade extension, the file is called facade-item.xml.

Item.xml file Overview

The order of the elements is maintained in the items.xml file since It is constantly checked against objects.xsd. The order that the elements must appear in items.xml has been defined in the xsd file if you do not adhere to the same order build won't work.

In a single pass, the items.xml file is processed and analyzed in running order. The items.xml file cannot be processed by the Hybris in multiple passes. As a result, types must be defined in the order of inheritance.

The items.xml file needs to have more definitions for concrete types closer to the finish and more definitions for abstract kinds closer to the beginning.

<items xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:noNamespaceSchemaLocation="items.xsd">
<atomictypes>
...
</atomictypes>
<collectiontypes>
...
</collectiontypes>
<enumtypes>
...
</enumtypes>
<maptypes>
...
</maptypes>
<relations>
...
</relations>
<itemtypes>
...
</itemtypes>
</items>