What is fetchXML?

FetchXML is proprietary query language used in Microsodt Dynamics CRM online or on-premises to retrieve records from an entity. It is depends on schema language. In terms of capabilities it is equal to queryexpression,  and it has addition feature of save query as user-owned saved view in userQuery system entity and and as an organization-owned saved view in the savedquery entity.

We will run FetchXML and retrieve records using RetrieveMultiple method by creating FetchExpression object.

Below is the sample code on running fetchXML.

String fetchXML=@"<fetch mapping='logical'>

   <entity name='account'>

      <attribute name='accountid'/>

      <attribute name='name'/>

</entity>

</fetch>";

FetchExpression fetchExpression=new FetchExpression(fetchXML);

EntityCollection entityCollection=service.RetrieveMultiple(fetchExpression);

Note: Don’t retrieve all attributes in a query because of the negative effect on performance. This is particularly true if the query is used as a parameter to an update request. In an update, if all attributes are included this sets all field values, even if they are unchanged, and often triggers cascaded updates to child records.