Web API types and operations

• 04/30/2019
• 8 minutes to read
• • J

In order to use the Web API you need to find information about what is available for you to use. The service describes itself via service and metadata documents that you can access. This topic will introduce important concepts and describe how you can find the information you need using documentation generated from the service and metadata documents as well as the documentation of the system entity types, functions, and actions.

Terminology

The Web API is implemented using the OData v4 standard which uses a specific set of terms you need to be familiar with. Entity Data Model (EDM) is the abstract data model that is used to describe the data exposed by an OData service. The following table is a selected list of terms defined in OData Version 4.0 Part 1: Protocol Plus Errata 02 which you should understand.

Service documents

There are two service documents you can reference to learn more about the Web API.

Service document

The following query, typed into the address field of your browser, returns the service document, a complete list of all the entity sets that are available for your organization. Note that [organization URI] represents the URL for your organization.

  
[Organization URI]/api/data/v9.0  
  

The entity sets are returned in the form of a JSON array. Each item in the array has three properties as listed in this table.

This information can be retrieved using a GET request and may be useful to get a list of all entity sets available using the service.

CSDL $metadata document

A GET request to the following URL will return a rather large (more than 3.5 MB) Common Schema Definition Language (CSDL) document, or metadata document that describes the data and operations exposed by the service.

GET [Organization URI]/api/data/v9.0/$metadata  

This document can be used as a data source to generate classes that will provide strongly typed objects for the service. But if you are not using generated classes, you may want to review documentation generated from this information instead. The Web API Reference uses information primarily from this document taken from a system with common additional solutions installed.

You can learn more about this document in OData Version 4.0 Part 3: Common Schema Definition Language (CSDL) Plus Errata 02.

Metadata annotations

The metadata document includes several types of Annotation elements which provide additional information about metadata elements and the capabilities of the service. Starting with v9.x, these annotations are not included with the default metadata document unless explicitly requested. These annotations increase the size of the metadata document and are not always necessary.

To include annotations you have two options when requesting the metadata document:

• Append the ?annotations=true query string parameter to the URL.

• Add the Prefer: odata.include-annotations="*" header to the request.

Each Annotation element includes a Term attribute that describes the type of annotation. The definitions of all the possible annotations used by OData v4 can be found in OData Vocabularies Version 4.0. The following table provides some examples used by the Web API.

Entity types

The Web API EntityType Reference lists each of the system entity types exposed through the web API which store business data. An entity type is a named structured type with a key. It defines the named properties and relationships of an entity. Entity types may derive by single inheritance from other entity types. Web API Metadata EntityType Reference lists each of the entity types used to manage system metadata. Both are entity types but the way you work with them is different. See Use the Web API with Microsoft Dataverse metadata for information about using model entities. Each entity type is included within an EntityType element in the $metadata. The following is the definition of the account EntityType from the $metadata with properties and navigation properties removed.

<EntityType Name="account" BaseType="mscrm.crmbaseentity">  
  <Key>  
    <PropertyRef Name="accountid" />  
  </Key>  
  <!--Properties and navigation properties removed for brevity-->  
  <Annotation Term="Org.OData.Core.V1.Description" String="Business that represents a customer or potential customer. The company that is billed in business transactions." />  
</EntityType>  

Each EntityType reference page in the SDK documentation uses information from the $metadata to show the following information when available.

Change the name of an entity set

By default, the entity set name matches the EntityMetadata EntityType LogicalCollectionName (EntityMetadataLogicalCollectionName) property value. If you have a custom entity that you want to address using a different entity set name, you can update the EntityMetadata EntityType EntitySetName (EntityMetadata.EntitySetName) property value to use a different name.

Alternate keys

Although Dataverse allows for creating alternate keys, only the primary key will be found in the default entities.

None of the system entities have alternate keys defined. If you define alternate keys for an entity, they will be included in the $metadata EntityType element as an Annotation like the following:

<Annotation Term="OData.Community.Keys.V1.AlternateKeys">  
  <Collection>  
    <Record Type="OData.Community.Keys.V1.AlternateKey">  
      <PropertyValue Property="Key">  
        <Collection>  
          <Record Type="OData.Community.Keys.V1.PropertyRef">  
            <PropertyValue Property="Alias" String="key name" />  
            <PropertyValue Property="Name" PropertyPath="key name" />  
          </Record>  
        </Collection>  
      </PropertyValue>  
    </Record>  
  </Collection>  
</Annotation>  

Information about alternate keys can also be retrieved from the metadata using the EntityMetadata EntityType Keys collection-valued navigation property using the Web API or the EntityMetadata.Keys property using the organization service.

Type inheritance

Inheritance allows for sharing of common properties and categorizing entity types into groups. All entity types in the web API inherit from two of the following entity types. All business entity types inherit from the crmbaseentity EntityType and all model entities inherit from the crmmodelbaseentity EntityType.

Properties

Each entity type may have declared properties that correspond to attributes. In the Web API EntityType Reference and Web API Metadata EntityType Reference content, properties that are inherited from a base entity type are combined within the list of declared properties for each entity type. The inheritance is called out in the description for each property.

In the $metadata EntityType elements each property is included in a Property element with a Name attribute value that corresponds to the properties you will set in code. The Type attribute value specifies the data type of the property. Properties for business entity types generally use OData primitive types.

The following is an example of the account EntityType name property defined in the $metadata.

<Property Name="name" Type="Edm.String" Unicode="false">  
  <Annotation Term="Org.OData.Core.V1.Description" String="Type the company or business name." />  
</Property>  

The description of the property is available in an Annotation element with the Term attribute property of Org.OData.Core.V1.Description. This description is taken from the AttributeMetadata EntityType Description property value. Not all properties have a description.

Each property may be computed. This means that the value may be set by the system. This is specified in an Annotation element with the Term attribute value of Org.OData.Core.V1.Computed.

Each property may also have limitations on whether it may be updated. This is defined in an Annotation element with a Term attribute value Org.OData.Core.V1.Permissions. The only option set for this is Org.OData.Core.V1.PermissionType/Read, which indicates that the property is read only.

Primitive types

OData supports a wide range of data types but Dataverse doesn’t use all of them. The following table describes how Dataverse Organization service types are mapped to OData primitive types.

Lookup properties

For most single-valued navigation properties you will find a computed, read-only property that uses the following naming convention: _<name>_value where the <name> matches the name of the single-valued navigation property. The exception to this pattern is when a lookup attribute of the entity can accept multiple types of entity references. A common example is how the incident entity customerid attribute may be set to a reference that is either a contact or account entity. In the incident EntityType Single-valued navigation properties you will find customerid_account and customerid_contact as separate single-valued navigation properties to reflect the customer associated with an opportunity. If you set one of these single-valued navigation properties, the other will be set to null because they are both bound to the customerid attribute. In the incident EntityType Properties you’ll find a _customerid_value lookup property that contains the same value that is set for whichever of the single-valued navigation properties contain a value.

Generally, you should avoid using lookup properties and use the corresponding single-valued navigation properties instead. These properties have been included because they may be useful for certain integration scenarios. These properties are read-only and computed because they will simply reflect the changes applied using the corresponding single-valued navigation property.

When you include lookup properties in a query, you can request annotations to be included that provide additional information about the data that is set for those underlying attributes which aren’t represented by a single-valued navigation property. More information:Retrieve data about lookup properties

Navigation properties

In OData, navigation properties allow you to access data related to the current entity. When you retrieve an entity you can choose to expand navigation properties to include the related data. There are two types of navigation properties: single-valued and collection-valued.

Single-valued navigation properties

These properties correspond to Lookup attributes that support many-to-one relationships and allow setting a reference to another entity. In the $metadata EntityType element, these are defined as a NavigationProperty element with at Type attribute set to a single type. The following is an example of the account EntityType createdby single-valued navigation property in the $metadata:

<NavigationProperty Name="createdby" Type="mscrm.systemuser" Nullable="false" Partner="lk_accountbase_createdby">  
 <ReferentialConstraint Property="_createdby_value" ReferencedProperty="systemuserid" />  
</NavigationProperty>  

Every navigation property that represents a single-valued navigation property will have a corresponding collection-valued navigation property indicated by the Partner attribute value. Each single-valued navigation property also has a ReferentialConstraint element with Property attribute value that represents the computed read-only lookup property that can be used to retrieve corresponding GUID value of the related entity. More information:Lookup properties

Collection-valued navigation properties

These properties correspond to one-to-many or many-to-many relationships. In the $metadata EntityType element, these are defined as a NavigationProperty element with at Type attribute set to a collection of a type. The following represents the account EntityType Account_Tasks collection-valued navigation property which represents a one-to-many relationship:

<NavigationProperty Name="Account_Tasks" Type="Collection(mscrm.task)" Partner="regardingobjectid_account_task" />  

When the collection-valued navigation property represents a many-to-many relationship, the name of the navigation property and the name of the partner will be the same. The following represents the account EntityType accountleads_association collection-valued navigation property which represents a many-to-many relationship:

<NavigationProperty Name="accountleads_association" Type="Collection(mscrm.lead)" Partner="accountleads_association" />  

The difference between one-to-many and many-to-many relationships is not important when using the Web API. The way you associate entities is the same regardless of the type of relationship. Although many-to-many relationships still use intersect entities behind the scenes, only a few special system intersect entities are included within the Web API EntityType Reference. For example, campaignactivityitem EntityType is technically an intersect entity, but it is included because it has more properties than an ordinary intersect entity.

An ordinary intersect entity has only the four basic properties required to maintain the many-to-many relationship. When you create a custom many-to-many relationship between entities, an ordinary intersect entity will be created to support the relationship. Because you should use navigation properties to perform operations involving many-to-many relationships, ordinary intersect entities are not documented but are still available using the Web API. These intersect entity types are accessible using an entity set name that uses the following naming convention: <intersect entity logical name>+’collection’. For example, you can retrieve information from the contactleads intersect entity type using [Organization URI]/api/data/v9.0/contactleadscollection. You should only use these ordinary intersect entities in situations where you wish to apply change tracking.

Actions

Actions are operations that allow side effects, such as data modification, and cannot be further composed in order to avoid non-deterministic behavior.

The Web API Action Reference topic lists each of the available system actions. More information:Use Web API actions.

Functions

Functions are operations that do not have side effects and may support further composition, for example, with additional filter operations, functions or an action

There are two types of functions defined in the Web API:

• The Web API Function Reference lists each of the available system functions.

• The Web API Query Function Reference topic lists functions which are intended to be used as criteria in a query.

More information:Use Web API functions

Complex types

Complex types are keyless named structured types consisting of a set of properties. Complex types are commonly used as property values in model entities, or as parameters or return values for operations.

Web API ComplexType Reference lists all the system complex types. The following is the WhoAmIResponse ComplexType from the $metadata.

<ComplexType Name="WhoAmIResponse">  
  <Property Name="BusinessUnitId" Type="Edm.Guid" Nullable="false" />  
  <Property Name="UserId" Type="Edm.Guid" Nullable="false" />  
  <Property Name="OrganizationId" Type="Edm.Guid" Nullable="false" />  
</ComplexType>  

Enumeration types

Enumeration types or EnumTypes are named primitive types whose values are named constants with underlying integer values.

Web API EnumType Reference lists all the system enumeration types. Enumeration types are named primitive types whose values are named constants with underlying integer values. The following is the AccessRights EnumType from the $metadata.

<EnumType Name="AccessRights">  
  <Member Name="None" Value="0" />  
  <Member Name="ReadAccess" Value="1" />  
  <Member Name="WriteAccess" Value="2" />  
  <Member Name="AppendAccess" Value="4" />  
  <Member Name="AppendToAccess" Value="16" />  
  <Member Name="CreateAccess" Value="32" />  
  <Member Name="DeleteAccess" Value="65536" />  
  <Member Name="ShareAccess" Value="262144" />  
  <Member Name="AssignAccess" Value="524288" />  
</EnumType>  

See also

Use the Dataverse Web API
Authenticate to Dataverse with the Web API
Perform operations using the Web API