Entity Relationships

Microsoft Dynamics CRM Online supports the following types of relationships:

• Hierarchical Relationships
• N:N (Many-to-Many) Relationships
• Self-Referential Relationships

Hierarchical Relationships

A hierarchical relationship allows each child record A record in a hierarchical relationship with a parent record where a reference to the parent record is stored in the record. One parent record can be related to many child records. Child records have lookup fields in the form to allow them to be related to a parent record. to store a reference to one parent record A record that is in a hierarchical relationship with a child record, where a reference to the record is stored in the child record. One parent record can be related to many child records.. A parent record can be referenced by an unlimited number of child records. The parent record can display all the child records in an associated view The view of an entity that is displayed in the forms of other entities. The associated view is different from the views that are visible for the entity in its own area of the user interface. For example, in an account record, under Details, you can click Contacts to view and open a contact form. That is the Contacts associated view. There can be only one associated view of each entity..

Hierarchical relationships provide opportunities to configure a number of behaviors that affect data integrity and the business rules in your organization. There are also limitations on the types of relationships that you can create. More information: Understanding Hierarchical Entity Relationships

When you create or edit a relationship between entities in Microsoft Dynamics CRM Online you must start from one of the entities. Which entity is not important because only one relationship will be created and only one relationship needs to be edited. The terminology used depends on whether you start from the primary entity The entity that a related entity is associated to. Sometimes called a parent entity. or the related entity An entity that is associated with a primary entity (record type) through a unique reference defined by using a lookup control on the related entity form. For example, an account has a unique reference to a primary contact..

• A 1:N Relationship is a hierarchical relationship created or viewed from the primary entity. Any one record from the primary entity can be referenced by many records from the related entity.
• A N:1 Relationship is a hierarchical relationship created or viewed from the related entity. Many records from the related entity can reference any one record from the primary entity.

Note: It is important to remember that the same relationship can be viewed from either of the two entities that participate in the relationship.

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N:N (Many-to-Many) Relationships

Microsoft Dynamics CRM Online Microsoft Dynamics CRM 4.0 introduces the ability to define a N:N Relationship between entities.

A N:N relationship allows users to relate one or more records from another entity to a record of the current entity. A N:N relationship is reciprocal, so records can be related from either entity. A N:N relationship may also be self-referential, meaning that one or more other records of the current entity can be related to a record of the same entity.

A list of any related records can be displayed in an associated view The view of an entity that is displayed in the forms of other entities. The associated view is different from the views that are visible for the entity in its own area of the user interface. For example, in an account record, under Details, you can click Contacts to view and open a contact form. That is the Contacts associated view. There can be only one associated view of each entity. available in the Navigation area of the current entity form and in the form of the other entity.

Users who are associated with a security role A defined set of privileges. The security role assigned to a user determines which tasks the user can perform and which parts of the user interface the user can view. All users must be assigned at least one security role in order to access the system. that provides Read and Append privileges to the current entity as well as Read, Write, and Append To privileges to the other entity will be able to relate records using this relationship.

Note: Microsoft Dynamics CRM Online 3.0 provided a N:N Relationship between the Opportunity and Competitor entities. N:N relationships in Microsoft Dynamics CRM Online Microsoft Dynamics CRM 4.0 work the same way.

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Self-Referential Relationships

Microsoft Dynamics CRM Online Microsoft Dynamics CRM 4.0 introduces the ability to define self-referential relationships.

Both hierarchical relationships and N:N relationships can be self-referential. This means that an entity can have a relationship with itself. This permits records to be directly associated with other records of the same type. For example, opportunities can be linked to related opportunities.

The only limitation to self-referential relationships is that records cannot be related to themselves in a parental A relationship between entities in which any action taken on a record of the parent entity is also taken on any child entity records that are related to the parent entity record. For example, if you delete a record in the parent entity, the related child entity records are also deleted; or if you share a parent entity record, the related records from the child entity are also shared. relationship. This would create a circular reference.

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Related Topics Customization Privileges Customizing Entities Customization Capabilities

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