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Retrieve an entity using the Web API

  • Artykuł

 

Applies To: Dynamics 365 (online), Dynamics 365 (on-premises), Dynamics CRM 2016, Dynamics CRM Online

Use a GET request to retrieve data for an entity specified as the resource with a unique identifier. When retrieving an entity you can also request specific properties and expand navigation properties to return properties from related entities.

Note

For information about retrieving entity metadata, see Query metadata using the Web API.

In this topic

Basic Retrieve example

Retrieve specific properties

Retrieve using an alternate key

Retrieve a single property value

Retrieve navigation property values

Retrieve related entities for an entity by expanding navigation properties

Options to apply to expanded entities

Detect if an entity has changed since it was retrieved

Retrieve formatted values

Basic Retrieve example

This example returns data for an account entity instance with the primary key value equal to 00000000-0000-0000-0000-000000000001.

GET [Organization URI]/api/data/v8.2/accounts(00000000-0000-0000-0000-000000000001)

To retrieve more than one entity at a time, see Basic query example in the Query Data using the Web API topic.

Caution

The above example will return all the properties for account record, which is against the performance best practices for retrieving data. This example was just to illustrate how you can do a basic retrieve of an entity instance in Dynamics 365. Because all the properties were returned, we haven't included the response information for the request in this example.

As a performance best practice, you must always use the $select system query option to limit the properties returned while retrieving data. See the following section, Retrieve specific properties, for information about this.

Retrieve specific properties

Use the $select system query option to limit the properties returned by including a comma-separated list of property names. This is an important performance best practice. If properties aren’t specified using $select, all properties will be returned.

The following example retrieves name and revenue properties for the account entity with the primary key value equal to 00000000-0000-0000-0000-000000000001

  • Request

    GET [Organization URI]/api/data/v8.2/accounts(00000000-0000-0000-0000-000000000001)?$select=name,revenue HTTP/1.1
Accept: application/json
Content-Type: application/json; charset=utf-8
OData-MaxVersion: 4.0
OData-Version: 4.0

  • Response

    HTTP/1.1 200 OK
Content-Type: application/json; odata.metadata=minimal
OData-Version: 4.0

{
"@odata.context": "[Organization URI]/api/data/v8.2/$metadata#accounts(name,revenue)/$entity",
"@odata.etag": "W/\"502186\"",
"name": "A. Datum Corporation (sample)",
"revenue": 10000,
"accountid": "00000000-0000-0000-0000-000000000001",
"_transactioncurrencyid_value":"b2a6b689-9a39-e611-80d2-00155db44581"
}

When you request certain types of properties you can expect additional read-only properties to be returned automatically.

If you request a money value, the _transactioncurrencyid_value lookup property will be returned. This property contains only the GUID value of the transaction currency so you could use this value to retrieve information about the currency using the transactioncurrency EntityType. Alternatively, by requesting annotations you can also get additional data in the same request. More information: Retrieve data about lookup properties

If you request a property that is part of a composite attribute for an address, you will get the composite property as well. For example, if your query requests the address1_line1 property for a contact, the address1_composite property will be returned as well. More information: Composite attributes.

Retrieve using an alternate key

If an entity has an alternate key defined, you can also use the alternate key to retrieve the entity instead of the unique identifier for the entity. For example, if the Contact entity has an alternate key definition that includes both the firstname and emailaddress1 properties, you can retrieve the contact using a query with data provided for those keys as shown here.

GET [Organization URI]/api/data/v8.2/contacts(firstname='Joe',emailaddress1='abc@example.com')

Any time you need to uniquely identify an entity to retrieve, update, or delete, you can use alternate keys configured for the entity. By default, there are no alternate keys configured for entities. Alternate keys will only be available if the organization adds them.

Retrieve a single property value

When you only need to retrieve the value of a single property for an entity, you can append the name of the property to the URI for an entity to return only the value for that property. This is a performance best practice because less data needs to be returned in the response.

This example returns only the value of the name property for an account entity.

  • Request

    GET [Organization URI]/api/data/v8.2/accounts(00000000-0000-0000-0000-000000000001)/name HTTP/1.1
Accept: application/json
OData-MaxVersion: 4.0
OData-Version: 4.0

  • Response

    HTTP/1.1 200 OK
Content-Type: application/json; odata.metadata=minimal
OData-Version: 4.0

{
"@odata.context":"[Organization URI]/api/data/v8.2/$metadata#accounts(00000000-0000-0000-0000-000000000001)/name",
"value":"Adventure Works (sample)"
}

Retrieve navigation property values

In the same way that you can retrieve individual property values, you can also access the values of navigation properties (lookup fields) by appending the name of the navigation property to the URI referencing an individual entity.

The following example returns the full name of the primary contact of an account using the primarycontactid single-valued navigation property.

  • Request

    GET [Organization URI]/api/data/v8.2/accounts(00000000-0000-0000-0000-000000000001)/primarycontactid?$select=fullname HTTP/1.1
Accept: application/json
OData-MaxVersion: 4.0
OData-Version: 4.0

  • Response

    HTTP/1.1 200 OK
Content-Type: application/json; odata.metadata=minimal
OData-Version: 4.0

{
"@odata.context": "[Organization URI]/api/data/v8.2/$metadata#contacts(fullname)/$entity",
"@odata.etag": "W/\"500128\"",
"fullname": "Rene Valdes (sample)",
"contactid": "ff390c24-9c72-e511-80d4-00155d2a68d1"
}

For collection-valued navigation properties you have the option to request to return only references to the related entities or just a count of the related entities.

The following example will just return references to tasks related to a specific account by adding /$ref to the request.

  • Request

    GET [Organization URI]/api/data/v8.2/accounts(00000000-0000-0000-0000-000000000001)/AccountTasks/$ref HTTP/1.1
Accept: application/json
OData-MaxVersion: 4.0
OData-Version: 4.0

  • Response

    HTTP/1.1 200 OK
Content-Type: application/json; odata.metadata=minimal
OData-Version: 4.0

{
"@odata.context": "[Organization URI]/api/data/v8.2/$metadata#Collection($ref)",
"value": [
{
"@odata.id": "[Organization URI]/api/data/v8.2/tasks(6b5941dd-d175-e511-80d4-00155d2a68d1)"
},
{
"@odata.id": "[Organization URI]/api/data/v8.2/tasks(fcbb60ed-d175-e511-80d4-00155d2a68d1)"
}
]
}

The following example returns the number of tasks related to a specific account using the Account_Tasks collection-valued navigation property with /$count appended.

  • Request

    GET [Organization URI]/api/data/v8.2/accounts(00000000-0000-0000-0000-000000000001)/Account_Tasks/$count HTTP/1.1
Accept: application/json
OData-MaxVersion: 4.0
OData-Version: 4.0

  • Response

    2

Note

The value returned includes the UTF-8 byte order mark (BOM) characters () that represent that this is a UTF-8 document.

Use the $expand system query option to control what data from related entities is returned. There are two types of navigation properties:

  • Single-valued navigation properties correspond to Lookup attributes that support many-to-one relationships and allow setting a reference to another entity.

  • Collection-valued navigation properties correspond to one-to-many or many-to-many relationships.

If you simply include the name of the navigation property, you’ll receive all the properties for related records. You can limit the properties returned for related records using the $select system query option in parentheses after the navigation property name. Use this for both single-valued and collection-valued navigation properties.

Note

To retrieve related entities for entity sets, see Retrieve related entities by expanding navigation properties.

  • Retrieve related entities for an entity instance by expanding single-valued navigation properties: The following example demonstrates how to retrieve the contact for an account entity. For the related contact record, we are only retrieving the contactid and fullname.

    • Request

      GET [Organization URI]/api/data/v8.2/accounts(00000000-0000-0000-0000-000000000001)?$select=name&$expand=primarycontactid($select=contactid,fullname) HTTP/1.1
Accept: application/json
OData-MaxVersion: 4.0
OData-Version: 4.0

    • Response

      HTTP/1.1 200 OK
Content-Type: application/json; odata.metadata=minimal
OData-Version: 4.0

{
"@odata.context":"[Organization URI]/api/data/v8.2/$metadata#accounts(name,primarycontactid,primarycontactid(contactid,fullname))/$entity",
"@odata.etag":"W/\"550616\"",
"name":"Adventure Works (sample)",
"accountid":"00000000-0000-0000-0000-000000000001",
"primarycontactid":{
"@odata.etag":"W/\"550626\"",
"contactid":"c59648c3-68f7-e511-80d3-00155db53318",
"fullname":"Nancy Anderson (sample)"
}
}

    Instead of returning the related entities for entity instances, you can also return references (links) to the related entities by expanding the single-valued navigation property with the $ref option. The following example returns links to the contact record for the account entity.

    • Request

      GET [Organization URI]/api/data/v8.2/accounts(00000000-0000-0000-0000-000000000001)?$select=name&$expand=primarycontactid/$ref HTTP/1.1
Accept: application/json
OData-MaxVersion: 4.0
OData-Version: 4.0

    • Response

      HTTP/1.1 200 OK
Content-Type: application/json; odata.metadata=minimal
OData-Version: 4.0

{
"@odata.context":"[Organization URI]/api/data/v8.2/$metadata#accounts(name,primarycontactid)/$entity",
"@odata.etag":"W/\"550616\"",
"name":"Adventure Works (sample)",
"accountid":"00000000-0000-0000-0000-000000000001",
"_primarycontactid_value":"c59648c3-68f7-e511-80d3-00155db53318",
"primarycontactid":{
"@odata.id":"[Organization URI]/api/data/v8.2/contacts(c59648c3-68f7-e511-80d3-00155db53318)"
}
}

    • Retrieve related entities for an entity instance by expanding collection-valued navigation properties: The following example demonstrates how you can retrieve all the tasks assigned to an account record.

      • Request

        GET [Organization URI]/api/data/v8.2/accounts(915e89f5-29fc-e511-80d2-00155db07c77)?$select=name&$expand=Account_Tasks($select=subject,scheduledstart)
Accept: application/json
OData-MaxVersion: 4.0
OData-Version: 4.0

      • Response

        HTTP/1.1 200 OK
Content-Type: application/json; odata.metadata=minimal
OData-Version: 4.0

{
"@odata.context":"[Organization URI]/api/data/v8.2/$metadata#accounts(name,Account_Tasks,Account_Tasks(subject,scheduledstart))/$entity",
"@odata.etag":"W/\"514069\"","name":"Sample Child Account 1","accountid":"915e89f5-29fc-e511-80d2-00155db07c77",
"Account_Tasks":[
{
"@odata.etag":"W/\"514085\"",
"subject":"Sample Task 1",
"scheduledstart":"2016-04-11T15:00:00Z",
"activityid":"a983a612-3ffc-e511-80d2-00155db07c77"
},{
"@odata.etag":"W/\"514082\"",
"subject":"Sample Task 2",
"scheduledstart":"2016-04-13T15:00:00Z",
"activityid":"7bcc572f-3ffc-e511-80d2-00155db07c77"
}
]
}

      Note

      If you expand on collection-valued navigation parameters to retrieve related entities for entity sets, a @odata.nextLink property will be returned instead for the related entities. You should use the value of the @odata.nextLink property with a new GET request to return the required data. More information: Retrieve related entities by expanding navigation properties

  • Retrieve related entities for an entity instance by expanding both single-valued and collection-valued navigation properties: The following example demonstrates how you can expand related entities for an entity instance using both single- and collection-values navigation properties.

    • Request

      GET [Organization URI]/api/data/v8.2/accounts(99390c24-9c72-e511-80d4-00155d2a68d1)?$select=accountid&$expand=parentaccountid($select%20=%20createdon,%20name),Account_Tasks($select%20=%20subject,%20scheduledstart) HTTP/1.1
Accept: application/json
Content-Type: application/json; charset=utf-8
OData-MaxVersion: 4.0
OData-Version: 4.0

    • Response

      HTTP/1.1 200 OK
Content-Type: application/json; odata.metadata=minimal
OData-Version: 4.0

{
"@odata.context":"[Organization URI]/api/data/v8.2/$metadata#accounts(accountid,parentaccountid,Account_Tasks,parentaccountid(createdon,name),Account_Tasks(subject,scheduledstart))/$entity","@odata.etag":"W/\"514069\"","accountid":"915e89f5-29fc-e511-80d2-00155db07c77",
"parentaccountid":{
"@odata.etag":"W/\"514074\"","createdon":"2016-04-06T00:29:04Z",
"name":"Adventure Works (sample)",
"accountid":"3adbf27c-8efb-e511-80d2-00155db07c77"
},"Account_Tasks":[
{
"@odata.etag":"W/\"514085\"",
"subject":"Sample Task 1",
"scheduledstart":"2016-04-11T15:00:00Z",
"activityid":"a983a612-3ffc-e511-80d2-00155db07c77"
},{
"@odata.etag":"W/\"514082\"",
"subject":"Sample Task 2",
"scheduledstart":"2016-04-13T15:00:00Z",
"activityid":"7bcc572f-3ffc-e511-80d2-00155db07c77"
}
]
}

Note

You can’t use the /$ref or /$count path segments to return only the URI for the related entity or a count of the number of related entities

Options to apply to expanded entities

You can apply certain system query options on the entities returned for a collection-valued navigation property. Use a semicolon-separated list of system query options enclosed in parentheses after the name of the collection-valued navigation property. You can use $select, $filter, $orderby, and $top.

The following example filters the results of task entities related to an account to those with a subject that ends with “1.”

GET [Organization URI]/api/data/v8.2/accounts(00000000-0000-0000-0000-000000000001)?$expand=Account_Tasks($filter=endswith(subject,'1');$select=subject)

The following example specifies that related tasks should be returned in ascending order based on the createdon property.

GET [Organization URI]/api/data/v8.2/accounts(00000000-0000-0000-0000-000000000001)?$expand=Account_Tasks($orderby=createdon asc;$select=subject,createdon)

The following example returns only the first related task.

GET [Organization URI]/api/data/v8.2/accounts(00000000-0000-0000-0000-000000000001)?$expand=Account_Tasks($top=1;$select=subject)

Note

This is a subset of the system query options described in the “11.2.4.2.1 Expand Options” section of OData Version 4.0 Part 1: Protocol Plus Errata 02. The options $skip, $count, $search, $expand and $levels aren’t supported for the Web API.

Detect if an entity has changed since it was retrieved

As a performance best practice you should only request data that you need. If you have previously retrieved an entity record, you can use the ETag associated with a previously retrieved record to perform conditional retrievals on that record. For more information, see Conditional retrievals.

Retrieve formatted values

Requesting formatted values for individual record retrievals is done the same way as done when querying entity sets. More information: Include formatted values.

See Also

Web API Basic Operations Sample (C#)
Web API Basic Operations Sample (Client-side JavaScript)
Perform operations using the Web API
Compose HTTP requests and handle errors
Query Data using the Web API
Create an entity using the Web API
Update and delete entities using the Web API
Associate and disassociate entities using the Web API
Use Web API functions
Use Web API actions
Execute batch operations using the Web API
Impersonate another user using the Web API
Perform conditional operations using the Web API

Microsoft Dynamics 365

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