CDS Annotations in SAP - 6

Core Data Services (CDS) views are a crucial component of the data model layer in SAP ABAP. They provide a strong abstraction over database tables and enable more declarative development of sophisticated views and queries. The use of annotations is one of CDS views’ primary characteristics. A CDS view‘s behavior and interactions with the database, user interfaces, and underlying system can be controlled by annotations, which offer metadata.

Because they specify how the view will behave in various runtime environments and system configurations, environment annotations are particularly significant among the different kinds of annotations. Depending on the execution context, these annotations aid in modifying the CDS view’s behavior, security, localization, and performance.

Table of Contents

Environment Annotations in CDS Views

Purpose: Environment annotations help define runtime characteristics such as database-specific optimizations, the language for texts, or whether certain features are enabled/disabled for the view.

Common Types of Environment Annotations:

@Environment.adding: Specifies that the annotation adds to or overrides the existing metadata.
@Environment.language: Used to indicate the language to be used for the text fields or labels.
@Environment.runtime: Controls how the view behaves in different runtime environments, such as in the cloud or on-premise.

Common Examples: Environment annotations are often used in conjunction with other annotations (like @AbapCatalog, @EndUserText, etc.) to specify system-specific behavior or configuration for the CDS view.

Use in Performance and Optimization:

Indexes: Annotations can guide the system in optimizing database queries for a specific environment.
Scalability: The annotations might adjust the CDS view for large-scale data or complex queries.
Security: In some cases, annotations control access rights and permissions on the data within a view.

Setting Language for a Field

@AbapCatalog.sqlViewName: 'ZMYCDSVIEW'
@EndUserText.label: 'My CDS View with Language'
@Environment.language: 'EN'
define view Z_MY_CDS_VIEW
  as select from scarr
{
  key carrid,
  @UI.lineItem: [{ position: 10 }]
  @Environment.language: 'DE'
  country
}

In this example, the @Environment.language annotation specifies the language for the text fields. This annotation helps in managing translations of field labels or data for multi-language support.

Enabling Read-Only Mode

@AbapCatalog.sqlViewName: 'ZREADONLYVIEW'
@EndUserText.label: 'Read-Only View Example'
@Environment.runtime: 'readonly'
define view Z_READ_ONLY_CDS_VIEW
  as select from sflight
{
  key carrid,
  connid,
  fldate,
  price
}

Here, the @Environment.runtime: 'readonly' annotation is applied to make the view behave in a read-only manner at runtime, preventing any data manipulation operations on the view.

Defining Performance Tuning for Specific Environment with CDS Annotations

@AbapCatalog.sqlViewName: 'ZPERFTUNING'
@EndUserText.label: 'Performance Tuned CDS View'
@Environment.adding: 'true'
define view Z_PERFORMANCE_TUNED_CDS_VIEW
  as select from sales_order
{
  key order_id,
  customer,
  order_date,
  total_amount
}

In this case, @Environment.adding: 'true' indicates that this view is being enhanced with additional performance-specific annotations for a particular environment.

Hierarchy-Annotations in CDS Views

The hierarchy Relationships between records in a hierarchical data structure, like a tree structure, are defined by annotations in CDS views. When it comes to representing organizational structures, bill-of-materials (BOMs), product hierarchies, and other hierarchical data models, CDS views’ ability to effectively manage parent-child relationships is made possible by these annotations.

Developers can create a clear and organized hierarchy by using hierarchy annotations to show which fields or records are connected to which fields or records. This makes it easier for users and SAP apps to view and work with hierarchical data.

Key Hierarchy Annotations in CDS Views

SAP provides several specific annotations that help define and manage hierarchical relationships in CDS views:

@Hierarchy.parentChildAssociation
@Hierarchy.level
@Hierarchy.structure
@Hierarchy.dependent

Let’s break down these annotations and their usage in more detail.

@Hierarchy.parentChildAssociation

This annotation is used to define the association between the parent and child entities in a hierarchical structure. It establishes a relationship between two entities where one acts as the parent and the other as the child, allowing for the representation of tree-like data.

@AbapCatalog.sqlViewName: 'ZBOM_HIERARCHY'
@EndUserText.label: 'Bill of Materials Hierarchy'
@Hierarchy.parentChildAssociation: 'Z_BOM_PARENT_CHILD_ASSOC'
define view Z_BOM_HIERARCHY
  as select from zbom_header as parent
  inner join zbom_item as child
    on parent.item_id = child.parent_item_id
{
  key parent.item_id,
  child.item_id as child_item,
  child.component_quantity
}

In this example:

The @Hierarchy.parentChildAssociation: 'Z_BOM_PARENT_CHILD_ASSOC' annotation defines the relationship between the parent (BOM header) and child (BOM items).
The association helps SAP applications understand that the parent.item_id is the parent entity, and the child.item_id is the child entity.

@Hierarchy.parentChild[ ].directory

The directory property can be defined as part of the @Hierarchy.parentChild annotation. Its main purpose is to define how the hierarchical structure should be navigated or represented in directories or tree structures, especially when working with large data sets that may have complex hierarchical relationships.

@Hierarchy.parentChild: { 
    'AssociationName', 
    directory: 'DirectoryName'
}

AssociationName: The parent-child association that establishes the connection between the parent and child records is referred to here.

directory: This designates a name or label for the directory that governs the appearance of the hierarchy, especially when it is presented in user interface situations (such as reports or Fiori apps that display hierarchical data as tree structures). The data may be filtered or grouped using the directory according to a hierarchical structure.

@Hierarchy.level

The @Hierarchy.level annotation specifies the hierarchical level of an element. This is particularly useful for organizing and visualizing data in a multi-level hierarchy, as it helps identify the depth of a record within the structure.

@Hierarchy.level: '1'
define view Z_BOM_LEVEL_ONE
  as select from zbom_header
{
  key item_id,
  description
}

Here, the @Hierarchy.level: '1' annotation indicates that the records in this view represent the first level of the hierarchy (e.g., the root elements). Similarly, you could use @Hierarchy.level: '2' to indicate child records in the next level.

@Hierarchy.structure

The @Hierarchy.structure annotation defines how the hierarchy is structured within the view. This annotation helps to identify and manage the hierarchical relationships more efficiently, especially when the data structure spans multiple levels.

@Hierarchy.structure: 'Z_BOM_STRUCTURE'
define view Z_BOM_STRUCTURE
  as select from zbom_header
{
  key item_id,
  item_id as parent_item,
  component
}

In this example, the @Hierarchy.structure: 'Z_BOM_STRUCTURE' annotation is used to group related fields or records together, forming the hierarchy structure for the Bill of Materials (BOM). This could represent multiple levels of BOM components where each item might have its own subcomponents, forming a multi-level hierarchical structure.

@Hierarchy.dependent

The @Hierarchy.dependent annotation indicates that the data in the view is dependent on the hierarchical structure defined by parent-child relationships. This is typically used when a child record’s validity or existence is determined by its parent record.

@Hierarchy.dependent: 'Z_BOM_DEPENDENT'
define view Z_BOM_DEPENDENT_ITEMS
  as select from zbom_item
{
  key item_id,
  component_id,
  quantity,
  @Hierarchy.dependent: 'Z_BOM_DEPENDENT'
  component_description
}

In this example:

The @Hierarchy.dependent: 'Z_BOM_DEPENDENT' annotation implies that the component_description is dependent on the parent-child relationship established in the BOM structure.

Why Use Hierarchy Annotations?

When creating CDS views, using hierarchy annotations offers the following significant benefits:

Clear Display of Hierarchical Data: In many business contexts, hierarchical data models—such as bill-of-materials, organizational structures, or product hierarchies—are prevalent. The relationships between parent and child records can be precisely defined and represented in a more organized and comprehensible manner by employing hierarchy annotations.

Better Navigation: Data that is organized hierarchically is easier to navigate thanks to hierarchy annotations. SAP applications can display data in a tree-like structure with the proper parent-child relationships and levels defined, which facilitates user interaction and visualization of complex data.

Performance Optimization: Because SAP systems are better able to comprehend the structure of data and how it should be retrieved, properly configured hierarchy connections can enhance query performance. This results in searches involving hierarchical data being executed more efficiently.

Integrity and Consistency: Dependencies between parent and child items are common in hierarchical data. In order to preserve data integrity and guarantee that modifications to the parent-child structure are appropriately recorded in the database, hierarchy annotations make sure that these connections are consistently represented.

Reporting Flexibility: Data must be presented in a hierarchical manner for reporting reasons (e.g., parent-child connections in organizational charts, BOMs, or product hierarchies). With the help of hierarchy annotations, CDS views may be used as a starting point for creating adaptable and dynamic reports.

CDS Annotations in SAP – 6